Measuring Circles Test Review

Front

What is the formula for the area of a circle?

Back

Area = πr², where r is the radius.

Front

What is the formula for the circumference of a circle?

Back

Circumference = 2πr or Circumference = πd, where r is the radius and d is the diameter.

Front

What does the area of a circle represent?

Back

The area represents the amount of space inside the circle.

Front

What does the circumference of a circle represent?

Back

The circumference represents the distance around the circle.

Front

If a circle has a radius of 3 units, what is its area?

Back

Area = π(3)² = 9π square units.

Front

If a circle has a diameter of 10 units, what is its circumference?

Back

Circumference = π(10) = 10π units.

Front

How is the circumference of a circle related to its diameter?

Back

The circumference is always π times the diameter.

Front

What is the relationship between radius and diameter?

Back

The diameter is twice the radius (d = 2r).

Front

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

Back

The area increases by a factor of four (Area = π(2r)² = 4πr²).

Front

If the radius of a circle is halved, how does the circumference change?

Back

The circumference is halved (Circumference = 2π(0.5r) = πr).