## RE: Passion, Purpose and Duty

On a bright Saturday afternoon of November, 2013 I had just finished doing my chores. I was very tired and just wanted to relax with my very entertaining soccer video game. Yes, I am a FIFA guy, FIFA 14 was hot and I was killing the tournament. I was at the finals of the tournament and there was so much pride, joy and contentment at the level I reached on the very tough game.

As I was about to start the finals match, I heard a knock on my door. Behold, it was my younger sister. She always came to me to help her solve her mathematics problems or assignments. She always complained that the teachers are doing magic when it comes to solving math and she gets lost in the steps. I noticed that after a while of helping her that the teachers do skip some steps when solving the math problem assuming that the students know them but alas most do not.

I have already started the game and I decided to joggle the both activities since the math problem she brought was on quadratic equation which is very simple for me as a second year engineering student. In the process of helping her understand how to use the almighty quadratic formula I was scored twice before half time and at half time I was able to have come back with a goal making it 1–2 (Me Versus Computer). I still pressed forward to the next half and along the way I was scored again and I was so angry. I ignored my sister to focus on just the game to know if I could come back. But I was only able to come back with a goal and the finals ended as 2–3 with me losing the tournament. I was so pissed off. I yelled! My sister on the hand was sad I did not aid her understand how to solve her math problem. She left the room unsatisfied.

In the midst of my vex I wished in my mind that there was something like a calculator encyclopedia that she can always use whenever she has a math problem just like a dictionary. No one would disturb you to tell you the meaning of a word. You simply tell them to go and check their dictionary and that’s all. I thought why is there nothing like that for calculations? Continue reading RE: Passion, Purpose and Duty

## How to Apply Sine Rule, Cosine Rule and Tangent Rule in Trigonometry

### Sine Rule

In trigonometry, the sine law, law of sines, sine rule, or sine formula is an rational equation that relates to the lengths of the sides of a triangle (any shape or kind) to the sines of its angles.

According to the sine rule,

a / sin(A) = b / sin(B) = c / sin(C)

where a, b, and c are the lengths of the sides of a triangle, and A, B, and C are the opposite angles.

Application of Sine Rule

• Sine rule can be used to find the unknown side or length of a triangle.
• Sine rule can also be used to find the unknown angle of a triangle.

To find the unknown side or length of a triangle, three essential parameters must be provided and these parameters are:

• The angle opposite to the unknown side or length of the triangle.
• The length of a side of the triangle (b).
• The angle opposite to the length of side (b) of the triangle.

Let’s take for example we have a triangle and we want to determine the unknown side of this triangle, when the opposite angle is given, another length of the side of the triangle and its opposite angle is also given. Like the image below.

From the image above, one can see that;
The angle opposite to the unknown length of the side of the triangle is 80°. (A)
The length of the side of the triangle given is 7. (b)
The angle opposite to the length of the side of the triangle given is 60° (B)
The unknown length of the side of the triangle is x. (a)

Applying the sine rule to find the value of x:

a / sin(A) = b / sin(B)

x / sin(80°) = 7 / sin(60°)
x / 0.9848 = 7 / 0.8660

Applying cross multiplication

x (0.8660) = 7 (0.9848)
x (0.8660) = 6.8936

Dividing both sides by 0.8660

x = 6.8936 / 0.8660
x = 7.96

Therefore, the unknown length of the side of the triangle, x is 7.96.

## How to Calculate and Solve for the Area, Base and Height of a Triangle | The Calculator Encyclopedia

The image above is a triangle.
To compute the area of a triangle two essential parameters are required which are the base of the triangle and the height of the triangle.

The formula for calculating the area of a triangle is:

A = 0.5bh

Where:

A = Area of a Triangle
b = Base of a Triangle
h = Height of a Triangle

Let’s solve an example:
Given that the base of a triangle is 12 cm and the height of the triangle is 4 cm. Find the area of the triangle.

This implies that:
b = Base of the Triangle = 12 cm
h = Height of the Triangle = 4 cm

A = 0.5bh
A = 0.5(12)(4)
A = 0.5(48)
A = 24

Therefore, the area of the triangle is 24 cm2

How to Calculate the Base of a Triangle when the Area and Height of the Triangle is Given

The formula is:

b = 2A / h

Where:

b = Base of the Triangle
A = Area of the Triangle
h = Height of the Triangle

Let’s take an example:
Find the base of a triangle when the height and area of the triangle is 12 cm and 40 cm2 respectively.

This implies that:
A = Area of the Triangle = 40 cm2
h = Height of the Triangle = 12 cm

b = 2(40) / 12
b = 80 / 12
b = 6.667

Therefore, the base of the triangle is 6.667 cm.

How to Calculate the Height of a Triangle when the Area and Base of the Triangle is Given

The formula is:

h = 2A / b

Where:

## How to Calculate and Solve for the Perimeter, Length and Width of a Rectangle | The Calculator Encyclopedia

The image above is a rectangle with a length of 8 cm and a width of 5 cm.
To compute the perimeter of a rectangle requires two parameters which are the length of the rectangle and the width of the rectangle.

The formula for calculating the perimeter of a rectangle is:

P = 2 (l + w)

Where:

P = Perimeter of a Rectangle
l = Length of a Rectangle
w = Width of a Rectangle

Let’s solve an example:
Find the perimeter of a rectangle where the length of the rectangle is 8 cm and the width of the rectangle is 5 cm.

This implies that:
l = Length of the Rectangle = 8 cm
w = Width of the Rectangle = 5 cm

P = 2 (l + w)
P = 2 (8 + 5)
P = 2 (13)
P = 26

Therefore, the perimeter of the rectangle is 26 cm.

How to Calculate the Length of a Rectangle when the Perimeter of the Rectangle and the Width of the Rectangle is Given

l = P / 2 – w

Where:
l = Length of the Rectangle
P = Perimeter of the Rectangle
w = Width of the Rectangle

## How to Calculate and Solve for the Area, Width and Length of a Rectangle | The Calculator Encyclopedia

The image above is a rectangle with a length of 9 cm and a width of 4 cm.
To compute the area of a rectangle requires two essential parameters which are the length of the rectangle and the width of the rectangle.

The formula for calculating the area of a rectangle is:

A = lw

Where:

A = Area of a Rectangle
l = Length of a Rectangle
w = Width of a Rectangle

Let’s solve an example
Find the area of a rectangle where the length of the rectangle is 9 cm and the width of the rectangle is 4 cm.

This implies that:
l = Length of the Rectangle = 9 cm
w = Width of the Rectangle = 4 cm

A = lw
A = (9)(4)
A = 36

Therefore, the area of the rectangle is 36 cm2.

How to Calculate the Length of a Rectangle when the Area and Width of the Rectangle is Given

The formula for calculating the length of the rectangle is:

l = A / w

Where:

l = Length of the Rectangle
A = Area of the Rectangle
w = Width of the Rectangle

Let’s solve an example:
Find the length of a rectangle where the area of the rectangle is 45 cm2 and the width of the rectangle is 9 cm.

This implies that:
A = Area of the Rectangle = 45 cm2
w = Width of the Rectangle = 9 cm

l = A / w
l = 45 / 9
l = 5

Therefore, the length of the rectangle is 5 cm.

How to Calculate the Width of a Rectangle when the Area and Length of the Rectangle is Given

The formula for calculating the width of the rectangle is:

w = A / l

Where:

w = Width of the Rectangle
A = Area of the Rectangle
l = Length of the Rectangle

## How to Calculate and Solve the Centre of Gravity of a Segment of a Sphere

The image above represents a segment of a sphere.
To compute the centre of gravity of a segment of a sphere requires two essential parameters. These parameters are the radius of the sphere and height of the segment of the sphere.

The formula for computing the centre of gravity of a sphere is:

C.G. = 3(2r – h)² / 4(3r – h)

Where:
C.G. = Centre of Gravity
r = Radius of the Sphere
h = Height of the Segment of the Sphere

Let’s solve an example
Find the centre of gravity of the segment of the sphere where the radius of the sphere is 10 m and the height of the segment of the sphere is 4 m.

This implies that:
r = Radius of the Sphere = 10
h = Height of the Segment of the Sphere = 4

C.G. = 3(2(10) – 4)² / 4(3(10) – 4)
C.G. = 3(20 – 4)² / 4(30 – 4)
C.G. = 3(16)² / 4(26)
C.G. = 3(256) / 104
C.G. = 768 / 104
C.G. = 7.38

Therefore, the centre of gravity of the segment of the sphere is 7.38.

Nickzom Calculator – The Calculator Encyclopedia is capable of calculating the centre of gravity of a segment of a sphere at a height, h at a distance from the centre of the sphere measured along the height.

## How to Calculate and Solve for the Centre of Gravity of a Cube

The image above is a cube with a length of 5.2 cm.
To compute the centre of gravity of a cube, one essential parameter is needed and this parameter is the length of the cube (l).

The formula for calculating the centre of gravity of a cube is:

C.G. = 0.5(l)

Where:
l = Length of the Cube
C.G. = Centre of Gravity

Let’s solve an example:
Find the centre of gravity of a cube where the length of a side of the cube is 5.2 cm.

This implies that:
l = Length of the Cube = 5.2

## How to Calculate and Solve for the Centroid or Centre of Gravity of a Hemisphere

The image above is a hemisphere with a radius of 5.
To compute the centroid or centre of gravity of a hemisphere. You need one essential parameter and this parameter is the radius of the hemisphere (r).

The formula for calculating the centroid or centre of gravity of a hemisphere is:

C.G. = 3r / 8

Where
r = Radius of the hemisphere

As always let us try and solve an example:
Find the centroid or centre of gravity of a hemisphere where the radius is 5 cm.

From the formula this implies that:
r = Radius of the hemisphere = 5

C.G. = 3(5) / 8
C.G. = 15 / 8
C.G. = 1.875

Therefore, the centroid or centre of gravity of the hemisphere is 1.875.

Nickzom Calculator – The Calculator Encyclopedia is capable of calculating the centre of gravity of a hemisphere at a distance from its base measured along the vertical radius.

To get the answer and workings of the center of gravity or centroid of a hemisphere using the Nickzom Calculator – The Calculator Encyclopedia. First, you need to obtain the app.

You can get this app via any of these means:

## Nickzom Calculator Calculates the Centroid or Centre of Gravity of a Semicircle | Statics (Mechanics)

The image above is a semicircle with a radius of 7 cm.
To compute the centroid or centre of gravity of a semicircle, you need one essential parameter and this parameter is the radius of the semicircle.

The formula for calculating the centroid or centre of gravity of a semicircle is:

C.G.= 4r /

Where:
r = Radius of the Semicircle
π = Mathematical Constant = 3.142 (approximately)

Let’s solve an example:
Find the centroid or centre of gravity of a semicircle where the radius is 7 cm.

From the example above,
r = radius of the semicircle = 7

C.G. = 4(7) /
C.G. = 28 / 9.4247
C.G. = 2.97

Therefore, the centroid or centre of gravity of the semicircle is 2.97.

Nickzom Calculator – The Calculator Encyclopedia is capable of calculating the centre of gravity of a semicircle at a distance from its base measured along the vertical radius.

To get the answer and workings of the center of gravity or centroid of a semicircle using the Nickzom Calculator – The Calculator Encyclopedia. First, you need to obtain the app.

## How to Calculate and Solve for the Centroid or Centre of Gravity of a Sphere

The image above is a sphere and 18 m is the diameter of the sphere. In the computing of the centroid or centre of gravity of a sphere there is only one essential parameter which is the diameter of the sphere.

The formula for calculating the centroid or centre of gravity of a sphere is:

C.G. = d / 2

Where:

d is the diameter of the sphere

As always, let’s take an example:

Let’s solve an example
Find the centroid or centre of gravity of a sphere where the diameter is 18 m.

C.G. = 18 / 2
C.G. = 9

Therefore, the centroid or centre of gravity of the sphere is 9.

Nickzom Calculator – The Calculator Encyclopedia is capable of calculating the centre of gravity of a sphere at a distance from every point.

To get the answer and workings of the center of gravity or centroid of a sphere using the Nickzom Calculator – The Calculator Encyclopedia. First, you need to obtain the app.

You can get this app via any of these means: