Finding the Circumference

Front

What is the formula for finding the circumference of a circle?

Back

C = π·d (where C is circumference and d is diameter)

Front

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

Back

C = π·d = 3.14·10 = 31.4 cm

Front

What is the relationship between radius and diameter?

Back

Diameter (d) = 2 × Radius (r)

Front

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

Back

C = 2·π·r = 2·3.14·5 = 31.4 inches

Front

What is the value of π (pi) used for calculations?

Back

Approximately 3.14 or 22/7

Front

How do you convert radius to diameter?

Back

Multiply the radius by 2.

Front

If a circle has a circumference of 62.8 cm, what is its diameter?

Back

d = C/π = 62.8/3.14 = 20 cm

Front

What is the circumference of a circle with a diameter of 8 feet?

Back

C = π·d = 3.14·8 = 25.12 feet

Front

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

Back

r = C/(2·π) = 31.4/(2·3.14) = 5 cm

Front

What is the circumference of a circle with a radius of 10 m?

Back

C = 2·π·r = 2·3.14·10 = 62.8 m