Question

Square ABCD has sides of length 15 ft. If the remaining part of the shape is a semicircle, what is the perimeter around the entire shape, to the nearest hundred?

Answer 1

See the following figure:

The square has sides of length = 15 ft

The semi-circle has a diameter = d = 15 ft

So, the radius = r = 15/2 = 7.5 ft

The perimeter of the figure is the outer distance of the shape

so, the perimeter =

3 sides of the square + the circumference of the semi-circle

So, the perimeter =

`\begin{gathered} 3\cdot15+0.5\cdot(2\pi\cdot r) \\ =3\cdot15+3.14\cdot7.5 \\ =45+23.55 \\ =68.55ft \end{gathered}`

So, the perimeter = 68.55 ft