Intro to Circles

Front

What is the diameter of a circle?

Back

The diameter is the distance across a circle through its center, equal to twice the radius.

Front

What is the radius of a circle?

Back

The radius is the distance from the center of the circle to any point on its circumference.

Front

What is the formula for the area of a circle?

Back

Area = π × r², where r is the radius.

Front

What is the formula for the circumference of a circle?

Back

Circumference = π × d, where d is the diameter.

Front

If the diameter of a circle is 16 cm, what is the radius?

Back

The radius is 8 cm.

Front

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

Back

Circumference = 2 × π × 5 cm ≈ 31.42 cm.

Front

What is the area of a circle with a radius of 7 cm?

Back

Area = π × 7² ≈ 153.94 cm².

Front

What is the relationship between diameter and radius?

Back

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

Front

What is the measure of a central angle in a circle?

Back

A central angle is an angle whose vertex is at the center of the circle and whose sides are radii.

Front

What is a chord in a circle?

Back

A chord is a line segment with both endpoints on the circle.