Question

Find the arc length of the semicircle.

Either enter an exact answer in terms of \piπpi or use 3.143.143, point, 14 for \piπpi and enter your answer as a decimal.

Answer 1

arc = 9π units

Explanation:

the arc is half the circumference of the circle, then

arc =
`(1)/(2)` × 2πr = πr , then

arc = π × 9 = 9π

Answer 2

`\boxed{\tt 9\pi }`

Explanation:

What we want to find here is the arc length of 1/2 of a circle, we'll start by finding the of the circle.

Step 1:- find the circumference of the circle →

`\boxed{\sf Circumference\; of\; the \:circle=2\pi r}`

`\tt 2\pi * 9`

`\tt 9* 2\pi`

`=\tt 18\pi`

Step 2:- find the arc length of 1/2 of the circle →

The arc length is 1/2 of the circumference of the circle:-

`\boxed{\sf Circumference \; of \;\cfrac{1}{2}\; of\; the \; circle=\cfrac{1}{2}* 18\pi}`

`\tt \cfrac{18}{2} \pi`

`\boxed{\tt 9\pi}`

Therefore, the arc length of the semicircle is 9π.