Radius and Diameter

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

How is the radius related to the diameter?

Back

The radius is half the diameter.

Front

What is the diameter of a circle?

Back

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

Front

If the radius of a circle is 10, what is the diameter?

Back

The diameter is 20.

Front

If the diameter of a circle is 30, what is the radius?

Back

The radius is 15.

Front

What is the formula to calculate the circumference of a circle using the radius?

Back

The circumference C is given by the formula C = 2πr, where r is the radius.

Front

What is the formula to calculate the area of a circle using the radius?

Back

The area A is given by the formula A = πr^2, where r is the radius.

Front

Is the radius always shorter than the diameter?

Back

Yes, the radius is always half the length of the diameter.

Front

What do you call a line segment that connects two points on a circle and passes through the center?

Back

That line segment is called the diameter.

Front

If a circle has a radius of 5, what is the circumference?

Back

The circumference is 10π (approximately 31.42).