Area and Circumference

Front

What is the formula for the circumference of a circle?

Back

C = π·d or C = 2·π·r

Front

What does the symbol π (pi) represent?

Back

π is approximately equal to 3.14.

Front

How do you calculate the circumference of a circle with a diameter of 10 cm?

Back

C = π·d = 3.14·10 = 31.4 cm.

Front

What is the area of a circle with a radius of 7 cm?

Back

Area = π·r² = 3.14·(7)² = 153.86 cm².

Front

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

Back

C represents the circumference of the circle.

Front

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

Back

C = 2·π·r = 2·3.14·5 = 31.4 cm.

Front

What is the area of a circle with a diameter of 8 cm?

Back

Area = π·r² = π·(4)² = 50.24 cm².

Front

What is the relationship between diameter and radius?

Back

Diameter (d) is twice the radius (r): d = 2·r.

Front

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

Back

r = C / (2·π).

Front

What is the circumference of a circle with a radius of 3 cm?

Back

C = 2·π·r = 2·3.14·3 = 18.84 cm.