Question

1. your answer both in terms of pi and also as a number

perimeter (terms of pi)
perimeter (number) 30.8

Explanation:

Step1: Find the arc - length of the semi - circle

The formula for the circumference of a full circle is $C = 2\pi r$. For a semi - circle, the arc - length $l$ is $\frac{1}{2}\times2\pi r=\pi r$. Given $r = 12$ cm, the arc - length $l=\pi\times12 = 12\pi$ cm.

Step2: Add the diameter to the arc - length

The diameter $d$ of the circle is $d = 2r=2\times12 = 24$ cm. The perimeter $P$ of the semi - circle is the sum of the arc - length and the diameter, so $P=12\pi + 24$ cm. In terms of $\pi$, the perimeter is $12\pi+24$ cm.

Step3: Calculate the numerical value

Substitute $\pi\approx3.14$. Then $P = 12\times3.14+24=37.68 + 24=61.68$ cm.

Answer:

Perimeter (terms of Pi): $12\pi + 24$ cm
Perimeter (number): $61.68$ cm