Circles - Exact and Approx.

Front

What is the formula for the area of a circle?

Back

The area of a circle is given by the formula: A = πr², where r is the radius.

Front

What is the formula for the circumference of a circle?

Back

The circumference of a circle is given by the formula: C = 2πr, where r is the radius.

Front

If the circumference of a circle is 36π cm, what is the radius?

Back

The radius is 18 cm, calculated using the formula C = 2πr.

Front

What is the relationship between diameter and radius?

Back

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

Front

What is the value of π (pi)?

Back

π (pi) is approximately 3.14, but it is an irrational number that continues infinitely.

Front

How do you calculate the area of a circle if you know the diameter?

Back

First, find the radius by dividing the diameter by 2, then use the formula A = πr².

Front

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

Back

The radius is 5 cm, since r = d/2.

Front

If the radius of a circle is 6 cm, what is the area?

Back

The area is 36π cm², calculated using A = π(6)².

Front

What is the exact circumference of a circle with a radius of 4 km?

Back

The exact circumference is 8π km, calculated using C = 2πr.

Front

What does the term 'exact area' mean in relation to circles?

Back

Exact area refers to the area calculated using the formula A = πr² without approximating π.