Circumference and Area of a Circle

Front

What is the formula for the circumference of a circle?

Back

C = 2πr or C = πd, where r is the radius and d is the diameter.

Front

What is the formula for the area of a circle?

Back

A = πr², where r is the radius.

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

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

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

Back

C = 2π(5) = 10π cm or approximately 31.42 cm.

Front

If the diameter of a circle is 10 cm, what is the area?

Back

A = π(5)² = 25π cm² or approximately 78.54 cm².

Front

What is π (pi)?

Back

π is a mathematical constant approximately equal to 3.14, representing the ratio of the circumference of a circle to its diameter.

Front

How do you convert diameter to radius?

Back

Radius = Diameter / 2.

Front

What is the circumference of a circle with a diameter of 12 cm?

Back

C = πd = π(12) = 12π cm or approximately 37.68 cm.

Front

What is the area of a circle with a radius of 3 m?

Back

A = π(3)² = 9π m² or approximately 28.27 m².