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The figures below are based on semicircles and squares. Find the perimeter and the area of each shape. Give your answer as a completely simplified exact value in terms of π (no approximations).

The figures below are based on semicircles and squares. Find the perimeter and the-example-1

1 Answer

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Answer:

A = 48cm²

P = 8cm + 24πcm OR P = 8(1 + 3π)cm

Explanation:

AREA

Calculate the total area. The whole shape looks complicated, but each semicircle was cut out on the original rectangle. The curved formed by AH fits into BC. CD fits in HG. GF fits in DE.

The area of the shape is a rectangle that is 12cm by 4cm.

A = lw

A = 12cm X 4cm

A = 48cm²

PERIMETER

The perimeter is 6 curved part (AH, HG, GF, BC, CD, DE) of semicircles and 2 sides of a square (AB and FE).

The curved parts on the semicircles are half of the circumference.

C = 2πr/2

C = πr

C = π(4cm)

C = 4πcm

Multiply by 6.

6C = 6*4πcm = 24πcm

Each side of the square is 4cm. Since there are 2 sides:

2 * 4cm = 8cm

Add the two numbers together.

P = 8cm + 24πcm

P = 8(1 + 3π)cm

User Ben Hamner
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