Circumference and Area of Circles & Semi-Circles

Front

What is the definition of diameter?

Back

Distance across the circle through the center.

Front

What is the distance around a circle called?

Back

Circumference.

Front

What is the perimeter of a semi-circle with a diameter of 10 yd?

Back

28.27 yd.

Front

If you fold a circle in half, what shape do you create?

Back

Semi-circle.

Front

What is the definition of radius?

Back

Distance from the center to any point on the circle.

Front

What is the formula for the circumference of a circle?

Back

C = πd or C = 2πr.

Front

What is the formula for the area of a circle?

Back

A = πr².

Front

What is the relationship between diameter and radius?

Back

Diameter is twice the radius (d = 2r).

Front

How do you find the area of a semi-circle?

Back

A = (πr²)/2.

Front

What is the circumference of a circle with a radius of 5 cm?

Back

C = 10π cm.