Parts of a Circle/Circumference of a Circle

Front

What is the measurement around the outside of a circle called?

Back

Circumference

Front

What is the distance from the center of a circle to any point on its circumference?

Back

Radius

Front

What is the distance across a circle through its center?

Back

Diameter

Front

If the radius of a circle is 9.5 mm, what is the diameter?

Back

19 mm (Diameter = 2 x Radius)

Front

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

Back

Circumference = 2πr (where r is the radius)

Front

If the circumference of a circle is 22.61 yd, what is the radius?

Back

Radius = Circumference / (2π) = 3.60 yd (approximately)

Front

What is the center of a circle?

Back

The point that is equidistant from all points on the circumference.

Front

If a circle has a diameter of 38 mm, what is its radius?

Back

19 mm (Radius = Diameter / 2)

Front

What is the relationship between radius and diameter?

Back

Diameter = 2 x Radius

Front

What is the circumference of a circle with a radius of 5 cm?

Back

Circumference = 2π(5) = 31.42 cm (approximately)