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

What is the diameter of a circle?

Back

The diameter is a straight line that passes through the center of the circle and touches two points on its circumference. It is twice the length of the radius.

Front

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

Back

The diameter is 10 cm (Diameter = 2 x Radius).

Front

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

Back

The radius is 8 ft (Radius = Diameter / 2).

Front

What is the relationship between radius and diameter?

Back

The diameter is always twice the length of the radius.

Front

What is the formula for the circumference of a circle?

Back

Circumference = 2 x π x Radius.

Front

What is the formula for the area of a circle?

Back

Area = π x (Radius)^2.

Front

Is the red line a radius or diameter of the circle? (If it connects the center to the circumference)

Back

Radius.

Front

Is the red line a radius or diameter of the circle? (If it connects two points on the circumference and passes through the center)

Back

Diameter.

Front

What is the circumference of a circle with a radius of 3 cm?

Back

Circumference = 2 x π x 3 cm ≈ 18.85 cm.