Area and Circumference of Circles and Central Arcs

If the radius of a circle is doubled, how does the area change?

• It doubles

• It triples

• It quadruples

• It remains the same

What is the diameter?

• 8

• 16

• 10

• 4

What is the area of this semi circle? 

• 100.5 square cm

• 25.1  square cm

• 50.3 square cm

• 12.6 square cm

What does r represent in the formula:

A = π·r²

• circumference

• radius

• diameter

• squared

What is the diameter?

• 8

• 16

• 10

• 4

What is the formula for the circumference of a circle?

What is the length of an arc with a central angle of 60 degrees in a circle with radius 3?

What is the area of a sector with a central angle of 90 degrees in a circle with radius 4?

In a circle, if the arc length is equal to the radius, what is the measure of the central angle in radians?

• 1 radian

• 2 radians

Fins the area of this quarter circle with a radius of 6 cm.

• 56.52 cm

• 113.04 cm

• 28.26 cm

• 37.68 cm