Circles

Front

What is the center of a circle?

Back

The center of a circle is the point that is equidistant from all points on the 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

How do you find the radius if you know the diameter?

Back

The radius is half of the diameter. If the diameter is 10 m, the radius is 5 m.

Front

What is the formula for the circumference of a circle?

Back

C = π·d, where C is the circumference and d is the diameter.

Front

How do you calculate the circumference if you know the radius?

Back

C = 2·π·r, where r is the radius.

Front

What is the diameter of a circle?

Back

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

Front

If a circle has a radius of 3 m, what is its diameter?

Back

The diameter is 6 m, since diameter = 2·radius.

Front

What is the approximate value of π (pi)?

Back

π is approximately 3.14.

Front

How do you find the circumference of a circle with a diameter of 6 m?

Back

C = π·d = π·6 m ≈ 18.84 m.

Front

What is the relationship between radius and circumference?

Back

The circumference can be calculated using the radius with the formula C = 2·π·r.