Circles - Retest

Front

What is the formula for the area of a circle?

Back

Area = π·r², where r is the radius.

Front

What does the symbol π (Pi) represent?

Back

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

Front

What is the circumference of a circle?

Back

The circumference is the distance around the circle, calculated using the formula C = π·d or C = 2·π·r.

Front

If a circle has a diameter of 10 feet, what is its radius?

Back

The radius is half of the diameter, so the radius is 5 feet.

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the length of the radius (d = 2·r).

Front

How do you calculate the circumference of a circle with a radius of 7 cm?

Back

C = 2·π·7 cm ≈ 43.98 cm.

Front

What is the area of a circle with a radius of 4 inches?

Back

Area = π·(4 in)² ≈ 50.27 in².

Front

What is the diameter of a circle if its circumference is 31.4 cm?

Back

Diameter = C/π = 31.4 cm/π ≈ 10 cm.

Front

What is the area of a circle with a diameter of 10 m?

Back

Area = π·(5 m)² ≈ 78.54 m².

Front

What does the term 'radius' refer to in a circle?

Back

The radius is the distance from the center of the circle to any point on its circumference.