Rectangular Prism

the formula you have to use to find the total surface area of a rectangular prism is A=LxW .

For example if you have a rectangular prism with a height of 6cm, Length of 10cm and a width of 4cm. To calculate the total surface area of the rectangular prism you have to use the formula.

Front and back : 6cm x 10cm

A= l x w

A= 10 x 6

A= 60 cm

A= 60 x 2

A= 120cm

Top and bottom: 4cm x 10cm

A= l x w

A= 10 x 4

A= 40cm

A= 40 x 2

A= 80cm

ends: 4cm x 6cm

A= l x w

A= 6 x 4

A= 24cm

A= 24 x 2

A= 48cm

A rectangular prism has 6 sides therefore you have to times it by 2 because there are two sides of the same area.

To get the total surface area you. add it all together

TSA= (area of front and back) + (area of top and bottom) + (area of ends)

TSA= 120 + 80 + 48

TSA= 248cm2

Triangular Prism

to find out the total surface area of a triangular prism the formula you need is A=L x W & B x H/2

For example if you have a length of 10cm, base of 4cm and a height of 5 here's what you have to do, to get the total surface area.

A=L x H

A= 10 x 3

A= 30cm

A= 30x3

A= 90cm

You times this by three since there are 3 equal sides.

A=B x H/2

A= 5 x 3/2

A= 7.5cm

A=7.5 x 2

A= 15cm

You times this by two because there are two sides of a triangle.

Now to get the total surface area you have to add these together.

TSA= (3 x area of a rectangle)+(2 x area of a triangle)

TSA= 90cm + 15cm

TSA= 105cm2

Cylnder

to find out the total surface area of a cylinder you have to use the formula R= d/2, A= L x W and C= pi x r x r

For example if you have a cylinder with a diameter of 2cm and the length being 15 cm. To find the total surface area you'll have to do this ..

R= d/2

R= 2/1

R= 1cm

C= pi x d

C= 3.14 x 2

C= 6.28 cm

A= pi x r x r

A= 3.14 x 1 x 1

A= 3.14

A= 3.14 x 2

A= 6.28

You times it by two because there are two circles. One end and the other.

A= L x W

A= 15 x 6.28

A= 94.2cm

TSA= (area of the circles x 2) + (area of the rectangle)

TSA= 3.14 + 3.14 + 94.2

TSA=100.48cm2

How to find the surface area of a rectangular prism.

http://www.ustream.tv/recorded/5160006

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