Area of Circles

Front

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

Back

A = π·r²

Front

What is the area of a circle with a radius of 5 cm?

Back

A = π·(5)² = 78.54 cm²

Front

What is the radius of a circle?

Back

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

Front

What is the diameter of a circle?

Back

The diameter is the distance across a circle through its center.

Front

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

Back

The area increases by a factor of four.

Front

What is π (pi)?

Back

π is a mathematical constant approximately equal to 3.14, representing the ratio of a circle's circumference to its diameter.

Front

How do you calculate the circumference of a circle?

Back

C = 2·π·r or C = π·d.

Front

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

Back

A = π·(5)² = 78.54 cm².

Front

What happens to the area of a circle if the radius is halved?

Back

The area decreases to one-fourth of the original area.

Front

What is the relationship between radius and diameter?

Back

The diameter is twice the radius (d = 2·r).