7.9B/7.9C Circles Test Review

Front

What is the area of a circle?

Back

The area of a circle is the amount of space inside the circle, calculated using the formula A = πr², where r is the radius.

Front

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

Back

The circumference of a circle is calculated using the formula C = 2πr or C = πd, where r is the radius and d is the diameter.

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the length of the radius. Formula: d = 2r.

Front

If the radius of a circle is 4 cm, what is the diameter?

Back

The diameter is 8 cm (d = 2r).

Front

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

Back

The radius is 5 cm (r = d/2).

Front

What is π (pi)?

Back

π (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 with a radius of 5 cm?

Back

Area = πr² = 3.14 * (5 cm)² = 78.5 cm².

Front

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

Back

First, find the radius: r = d/2 = 5 cm. Then, Area = πr² = 3.14 * (5 cm)² = 78.5 cm².

Front

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

Back

Circumference = 2πr = 2 * 3.14 * 3 cm = 18.84 cm.

Front

True or False: The radius is half of the diameter.

Back

True.