Answer:
15.71 cm
Explanation:
remember the formula for the circumference of a circle but make it half since it's a semi-circle
the perimeter of a circle is diameter x pi
since
the diameter is 10 and pi is 3.142
its 10 x 3.142
and that equals
31.42
that's a FULL circle so half of that
divide it by 2
31.42/2=15.71
so the diamater of the semi-circle is 15.71
hope this helps!
dont forget is centimeters