Radius, Diameter, Circumference Review

Front

What is the formula to find the circumference of a circle?

Back

Circumference = 2 × π × radius or Circumference = π × diameter.

Front

What is the relationship between radius and diameter?

Back

Diameter is twice the radius. (Diameter = 2 × radius) or (Radius = Diameter / 2).

Front

If the radius of a circle is 1.5 m, what is the diameter?

Back

Diameter = 2 × radius = 2 × 1.5 m = 3 m.

Front

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

Back

Radius = Diameter / 2 = 10 cm / 2 = 5 cm.

Front

Find the circumference of a circle with a radius of 3 m.

Back

Circumference = 2 × π × 3 m ≈ 18.84 m.

Front

What is the value of π (pi) approximately?

Back

π (pi) is approximately 3.14.

Front

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

Back

Radius = Circumference / (2 × π) = 31.4 cm / (2 × 3.14) = 5 cm.

Front

What does the term 'circumference' refer to?

Back

Circumference is the distance around the circle.

Front

If the circumference of a circle is 62.8 m, what is the diameter?

Back

Diameter = Circumference / π = 62.8 m / 3.14 = 20 m.

Front

What is the formula to find the area of a circle?

Back

Area = π × radius².