(REVIEW) Circles (radius, diameter, center)

Front

What is the definition of a radius in a circle?

Back

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

Front

What is the definition of a diameter in a circle?

Back

The diameter is the distance across the circle through its center, equal to twice the radius.

Front

How do you calculate the diameter if you know the radius?

Back

Diameter (d) = 2 × Radius (r).

Front

How do you calculate the radius if you know the diameter?

Back

Radius (r) = Diameter (d) ÷ 2.

Front

What is the center of a circle?

Back

The center is the point that is equidistant from all points on the circumference of the circle.

Front

If the radius of a circle is 3 m, what is the diameter?

Back

Diameter = 2 × 3 m = 6 m.

Front

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

Back

Radius = 10 cm ÷ 2 = 5 cm.

Front

What is the relationship between radius and diameter?

Back

The diameter is always twice the length of the radius.

Front

If a circle has a radius of 4 ft, what is the circumference? (Use C = 2πr)

Back

Circumference = 2 × π × 4 ft ≈ 25.13 ft.

Front

What is the formula for the area of a circle?

Back

Area = π × r².