Parts of a Circle And Circumference of a Circle

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 diameter of a circle?

Back

The diameter is twice the length of the radius and is the distance across the circle through its center.

Front

What is the circumference of a circle?

Back

The circumference is the distance around the circle, calculated as C = 2πr or C = πd.

Front

What is the value of pi (π)?

Back

Pi (π) is approximately 3.14 and represents the ratio of the circumference of a circle to its diameter.

Front

How do you calculate the circumference of a circle with a radius of 9 cm?

Back

C = 2πr = 2 × π × 9 cm ≈ 56.55 cm.

Front

What part of a circle is represented by a line from the center to the edge?

Back

This line is called the radius.

Front

What part of a circle is represented by a line that passes through the center and touches both sides of the circle?

Back

This line is called the diameter.

Front

If the diameter of a circle is 18 cm, what is the radius?

Back

The radius is half of the diameter, so the radius is 9 cm.

Front

What is the formula for the circumference of a circle using diameter?

Back

C = πd, where d is the diameter.

Front

What is the relationship between radius and diameter?

Back

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