Semicircle radius: 10 divided by 2=5.

10×5=50

5×5×3. 14 divided by 2=39.25

50-39.25= 10.75

Circumference:

( 10+5)×2=30

10×3. 14 divided by 2= 15.7.

30- 15.7= 14.3

I figured it out. I don't know if it's right.

I don't understand the first picture.