How to find perimeter of semicircle

1/2 π * d + d where d is the diagonal

Step-by-step explanation:

The perimeter of a circle is π * d where d is the diameter so half of that is 1/2 π * d. But If you are going to walk around a semicircle you need to go half way around the circle and then across a diagonal to get back to where you started so the perimeter is 1/2 π * d + d.