Circumference & Area of Circles

Front

What is the definition of a radius in a circle?

Back

The radius of a circle is the measurement from the center of the circle to any point on its edge.

Front

What is the definition of a diameter in a circle?

Back

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

Front

How do you calculate the circumference of a circle?

Back

The circumference of a circle can be calculated using the formula C = 2πr, where r is the radius.

Front

What is the formula for the area of a circle?

Back

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

Front

If the radius of a circle is doubled, how does the circumference change?

Back

If the radius is doubled, the circumference also doubles.

Front

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

Back

The radius is 5 cm, since the radius is half of the diameter.

Front

What is the relationship between diameter and radius?

Back

The diameter is twice the length of the radius (D = 2r).

Front

Calculate the circumference of a circle with a radius of 5 cm.

Back

The circumference is 31.4 cm (C = 2π(5)).

Front

If the circumference of a circle is 62.8 cm, what is the radius?

Back

The radius is 10 cm (C = 2πr, so r = C/(2π)).

Front

What is the area of a circle with a radius of 3 m?

Back

The area is approximately 28.3 m² (A = π(3)²).