Area of Circles

Front

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

Back

Area = π × r², where r is the radius of the circle.

Front

What does 'π' (pi) represent in circle calculations?

Back

π (pi) is a constant approximately equal to 3.14, used in calculations involving circles.

Front

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

Back

Area = π × (5 cm)² = 78.54 cm².

Front

What is the radius of a circle?

Back

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

Front

What is the diameter of a circle?

Back

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

Front

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

Back

Radius = Diameter ÷ 2 = 10 cm ÷ 2 = 5 cm.

Front

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

Back

Area = π × (7 cm)² = 153.94 cm².

Front

How does increasing the radius affect the area of a circle?

Back

Increasing the radius increases the area, as area is proportional to the square of the radius.

Front

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

Back

Area = π × (10 cm)² = 314.16 cm².

Front

What is the relationship between radius and diameter?

Back

The diameter is always twice the radius.