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17 votes
Find the surface area of the prism?
I will give whoever answers correctly a thanks!

Find the surface area of the prism? I will give whoever answers correctly a thanks-example-1
User Waqas Noor
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2 Answers

25 votes
25 votes
72+ 18+ 30+ 36 = 156 inches
User Steve Hibbert
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11 votes
11 votes

Answer:

To find the surface area, we must find the area of each and every individual side of this prism;

Before this we need to know the formula for area of a trapezoid:-

A = 1/2 x (b1 + b2) x h

where b1 is base one, and b2 is base two, h is the height

Now we find the area of the trapezoid above;

Bottom base 12, above base 6.

Height is 4.

Plug into our formula;

A = 1/2 x (b1 + b2) x h

A = 1/2 x (12 + 6) x 4

A = 1/2 x 18 x 4

A = 2 x 18

A = 36, the area of the trapezoid below will also be 36 because they are the same, so (36 + 36) = 72.

Now the area of the backside rectangle;

(formula for rectangle: A = L x W)

The width is 12.

The length is 3.

Plug in the values into our formula:-

A = L x W

A = 3 x 12

A = 36

Now the area of the front rectangle;

The base is 6.

The length is 3.

Plug in the values into our formula:-

A = L x W

A = 3 x 6

A = 18

Area of side rectangles(both have same area);

Base is 5.

Length is 3.

A = L x W

A = 3 x 5

A = 15, double of 15 (15 x 2) = 30.

Now we add all the areas:

72 + 36 + 18 + 30

= 156 inches, is the surface area.

User Arkni
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2.6k points