Basic Circle - Radius, Diameter, Circumference, Area

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

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 formula for the circumference of a circle?

Back

C = π·d, where C is the circumference and d is the diameter.

Front

What does the symbol π (pi) represent?

Back

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 calculate the area of a circle?

Back

Area = π·r², where r is the radius of the circle.

Front

What is the circumference of a circle with a diameter of 10 cm?

Back

C = π·d = π·10 cm ≈ 31.4 cm.

Front

If the radius of a circle is 5 meters, what is the diameter?

Back

The diameter is 10 meters (diameter = 2 × radius).

Front

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

Back

Area = π·r² = π·(3 cm)² ≈ 28.26 cm².

Front

What does 'circumference' mean?

Back

Circumference is the distance around a circle.

Front

If the circumference of a circle is 62.8 cm, what is the radius?

Back

Radius = C/(2π) = 62.8 cm/(2π) ≈ 10 cm.