Use 3.14 for π. Round answers to the nearest hundredth if necessary.

Question

The figure shows a circle with a point Upper X labeled at the center.

Calculate the area of Circle X if the diameter is 13 inches.

____ square inches

Calculate the radius of Circle X if the circumference is 138.16 square millimeters.

______millimeters

Answer 1

(a) recall that area = πr^2
r = 13/2, so area = π * (13/2)^2

(b) recall that C = 2πr
2πr = 138.16, so r = 138.16 / 2π

Answer 2

Okie thanks!

Answer 3

Since 3.14 is the standard number for pi in middle school, you would need that to multiply to the radius. 3.14 times ____(whatever is the radius) or sometimes it could be 2 times 3.14 times _____(whatever is the diameter). Just multiply your diameter to your "pi" then round it to the nearest hundredth if needed.

Basic formulas to remember:

d=2r
r=d/2
c=pi2r
c=2pir
d=c/pi
c=pid
Hope this helped!(or not-)
*If this was difficult or hard to understand from this comment, just search up circle fundamentals and learn the circumference steps!

Answer 4

Thanks!

Answer 5

Aaa

Answer 6

138.16