Area of Circles and Composite Figures

Front

What is the formula for the area of a circle?

Back

Area = πr², where r is the radius of the circle.

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 length of the radius and is the distance across the circle through its center.

Front

How do you find the area of a triangle?

Back

Area = 1/2 × base × height.

Front

What is a composite figure?

Back

A composite figure is a shape that is made up of two or more simple shapes.

Front

How do you find the area of a composite figure?

Back

Find the area of each simple shape and then add them together.

Front

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

Back

Area = π(3 cm)² = 28.27 cm² (approximately).

Front

What is the area of a triangle with a base of 6 in and a height of 4 in?

Back

Area = 1/2 × 6 in × 4 in = 12 in².

Front

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

Back

The area increases by a factor of four (Area = π(2r)² = 4πr²).

Front

What is the area of a shaded region in a circle if the area of the circle is 50 cm² and the area of the unshaded part is 20 cm²?

Back

Area of shaded region = Area of circle - Area of unshaded part = 50 cm² - 20 cm² = 30 cm².