Circles Perimeter and Radius

What is the radius?

• 28

• 15

• 26

• 13

What is the diameter?

• 6.5

• 15

• 26

• 78

The radius is....

• a line that crosses through the center and touches each edge 

• the center point of a circle 

• a line from the center point to the edge of the circle

• an element in science

A bicycle tire has a diameter of 27 inches. What is the radius?

• 27pi

• 13.5

• 81

• 25pi

A bicycle tire has a diameter of 27 inches. How far does the bike travel along the ground when the wheel rotates once? What is the circumference of this tire?

• 81

• 15.5

• 27

• 13

After taking part in a competition, Yahir received a bronze medal with a radius of 2.5 inches. What is the medal's diameter?

• 2.5 in

• 5 in

• 4 in

• 4.5 in

The distance around a circular track is 31.4 yards. What Is the radius of the track?

• r=10

• r=5

• r=98.6

What is the perimeter of this semi circle? (Use 3.14 = π and round to the nearest tenths place)

• 12.6

• 20.6

• 25.1

• 33.1

The perimeter of a circle is also known as the ______of the circle

• area

• arc

• circumference

Can you say that the circumference of a circle is always more than three times its diameter?

• Yes

• No