Question

The shape shown consists of three sides of a rectangle together with a semicircle. Which of the following is

closest to the perimeter of the shape? (The dashed line is not a part of the perimeter.
(1) 56.1
(2) 44.6
(3) 38.3
(4) 32.5

Answer 1

The perimeter of the shape is 32.5

Explanation:

Since the dashed line is not a perimeter,

we add the circumference of the circle plus the 3 sides of the rectangle

The circumference is of the half circle with its diameter being the opposite side of the rectangle

The opposite side is the length 10

So the radius is half of this which is 10/2 = 5

The circumference of the semicircle is thus;

pi * r = 22/7 * 5 = 15.71

full circle is 2 * pi * r

semi is half of full so we divide formula by 2

So let’s add up

15.71 + 10 + 3.4 + 3.4 = 32.51