how do i solve this any one know pls help me

Answer: 5π OR 15.70796327
Step-by-step explanation:
Formula for circumference is C=2πr (radius) OR C=πd (diameter)
Our radius is 5 units, so our diameter is 10 units
C=10π
However, the question is only asking for length of semicircle
So you have to divide: 10π/2=5π