Intro to Circles

Front

What is the definition of a circle?

Back

A circle is a set of points in a plane that are equidistant from a fixed point called the center.

Front

What is the diameter of a circle?

Back

The diameter is a line segment that passes through the center of the circle and has its endpoints on the circle.

Front

What is the radius of a circle?

Back

The radius is a line segment from the center of the circle to any point on the circle.

Front

What is the formula for the circumference of a circle?

Back

Circumference = 2πr, where r is the radius.

Front

What is the formula for the area of a circle?

Back

Area = πr², where r is the radius.

Front

What does the term 'circumference' refer to?

Back

Circumference refers to the distance around the circle.

Front

If the radius of a circle is 5 cm, what is the diameter?

Back

Diameter = 2 * radius = 2 * 5 cm = 10 cm.

Front

If the diameter of a circle is 12 cm, what is the radius?

Back

Radius = diameter / 2 = 12 cm / 2 = 6 cm.

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the length of the radius.

Front

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

Back

Circumference = 2πr = 2 * π * 7 cm ≈ 43.98 cm.