Circumference of a Circle

Front

What is the formula for the circumference of a circle?

Back

C = π·d or C = 2π·r, where C is circumference, d is diameter, and r is radius.

Front

If a circle has a radius of 10 cm, what is its circumference?

Back

C = 2π·10 = 62.83 cm (approximately 63 cm).

Front

What does the symbol π (pi) represent?

Back

π (pi) 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 find the diameter of a circle if you know the circumference?

Back

Diameter can be found using the formula: d = C/π.

Front

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

Back

C = 2π·5 = 31.42 m (approximately 31 m).

Front

What is the relationship between radius and diameter?

Back

The diameter is twice the radius: d = 2r.

Front

If the circumference of a circle is 31.4 cm, what is the radius?

Back

r = C/(2π) = 31.4/(2π) = 5 cm.

Front

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

Back

C = π·12 = 37.68 inches (approximately 38 inches).

Front

What does C represent in the formula C = π·d?

Back

C represents the circumference of the circle.

Front

If a circle has a circumference of 100 cm, what is its diameter?

Back

d = C/π = 100/π ≈ 31.83 cm.