Area and Circumference

Front

What is the formula for calculating the area of a circle?

Back

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

Front

What is the formula for calculating the circumference of a circle?

Back

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

Front

What is the value of π (pi) to two decimal places?

Back

The value of π (pi) is approximately 3.14.

Front

If the radius of a circle is 5 cm, what is its area?

Back

The area of the circle is A = π(5)² = 78.5 cm².

Front

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

Back

The circumference of the circle is C = πd = π(10) = 31.4 cm.

Front

What is the relationship between diameter and radius?

Back

The diameter of a circle is twice the length of the radius (d = 2r).

Front

How do you convert diameter to radius?

Back

To convert diameter to radius, divide the diameter by 2 (r = d/2).

Front

What is the area of a circle with a radius of 7 cm?

Back

The area of the circle is A = π(7)² ≈ 153.94 cm².

Front

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

Back

The circumference of the circle is C = 2π(3) ≈ 18.84 cm.

Front

What is the diameter of a circle with a radius of 4 cm?

Back

The diameter of the circle is d = 2r = 2(4) = 8 cm.