Finding the Radius or Diameter of a Circle

Find the radius of the circle

• 20 ft

• 10 ft

• 5.5 ft

• 10 inches

The definition of radius is

• distance from one point to another point

• distance around the circle

• distance from the center to any point on the circle

• distance across the circle through the center

The definition of diameter is

• distance from the center of any point on the circle

• distance across the circle through the center

• distance from one point to another

• distance around the circle

When given the diameter (d), how do you find the radius (r)? ​ (a)  

What is the radius?

• 18

• 72

• 38

• 14

what is the formula for finding radius (a)  

• c = π d

• c = 2 π r

• d = r/2

• r = d/2

What is the radius of this circle?

• 18

• 10

• 9

• 8

How many cookies are there?

• 48 cookies

• 24 cookies

• 8 cookies

• 4 cookies

find the diameter of the circle

• 14 m

• 7 m

• 14 yds

• 3.5 m

find the radius of the circle

• 3 m

• 1.5 m

• 1.5 in

• 1.5 mm