Circumference and arc length

Front

What is the formula for the circumference of a circle?

Back

The circumference (C) of a circle is given by the formula: C = 2πr, where r is the radius.

Front

What is the relationship between diameter and radius?

Back

The diameter (d) of a circle is twice the radius (r): d = 2r.

Front

What is the formula for the arc length of a circle?

Back

The arc length (L) can be calculated using the formula: L = \frac{central\ angle\ (degrees)}{360} \times 2\pi r.

Front

What is the circumference of a circle with a radius of 4.5 inches?

Back

C = 2π(4.5) = 28.26 inches.

Front

What is the circumference of a circle with a diameter of 20 km?

Back

C = πd = π(20) = 20π km.

Front

What is the central angle in degrees for a full circle?

Back

The central angle for a full circle is 360 degrees.

Front

What is the formula to find the radius from the circumference?

Back

To find the radius (r) from the circumference (C), use the formula: r = \frac{C}{2\pi}.

Front

What is the area of a circle?

Back

The area (A) of a circle is given by the formula: A = πr^2.

Front

What is the arc length for a central angle of 165 degrees in a circle with a radius of 24 feet?

Back

L = \frac{165}{360} \times 2\pi(24) = 69 ft.

Front

What is the difference between circumference and arc length?

Back

Circumference is the total distance around a circle, while arc length is the distance along a portion of the circle.