Area and Circumference of Circles and Central Arcs

what is the area of this semicircle ?
d = 8 cm 

• 100.48 cm²

• 80 cm²

• 200.96 cm²

• 25.12 cm²

what is the formula for finding the area of a semi-circle

• A = π r²

• C = π r²

• A = π r² / 2

• A = 2 π r

If the radius of a circle is 7 cm, what is the length of the arc subtended by a central angle of 60 degrees?

What is the area of a sector with a central angle of 90 degrees in a circle of radius 10 cm?

If the circumference of a circle is 30 cm, what is the radius?

A circle has a radius of 5 cm. What is the length of an arc that subtends an angle of 180 degrees?

Find the circumference of the circle. Round to the nearest hundredth.

Find the area of the circle. Round to the nearest hundredth.

• UT = 42

  WT = 42

  ST = 42

  XT = 56*

  ST = 136*

  US = 112*

• UT = 21

  WT = 21

  ST = 21

  XT = 112*

  ST = 136*

  US = 56*

• UT = 42

  WT = 21

  ST = 42

  XT = 56*

  ST = 112*

  US = 136*