Answer:
8. C=131.88 mm
9. C=40.82 ft
10. A=254.34 in²
Step-by-step explanation:
8. diameter of 42 millimeters- circumference?
Radius is half of 42, so 21 mm
Circumference=2πr
C=2π21
C=131.88 mm
9. diameter of 13 ft- circumference?
radius is half of 13, so 6.5
Circumference=2πr
C=2π6.5
C=40.82 ft
10. radius of 9 in- area?
Area=πr²
A=π9²
A=π81
A=254.34 in²