Question

What is the area and perimeter of a semicircle with a diameter of 10 cm?

Answer 1

See below.

Explanation:

Okay, you will need to know these two formulas to solve:

`A = pir^2` and `C=2pir`,

where `A` is the area of the circle, `C` is the circumference (or perimeter), and `r` is the radius.

Also, `d = 2r`, where d is diameter.

Now, plug in `10` cm (the diameter) into this equation to find the radius of the given circle (as `d`).

`d = 2r`
`(10) = 2r`
`r= 5" cm"`

Now, you can use the radius that you found and the first two equations that I mentioned to find the area and perimeter of the circle.

`A = pir^2`
`A=pi(5" cm")^2`

`C=2pir`
`C=2pi(5" cm")`

Now, you can enter this into your calculator, where `pi` is about `3.14`.

After doing so, you should get the two following numbers:

`A=78.5" cm"^2`
`C=30.9" cm"`

These are your two answers!

I hope that helped!