Area and Sectors of a Circle

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 a sector of a circle?

Back

A sector is a portion of a circle enclosed by two radii and the arc between them.

Front

How do you calculate the area of a sector?

Back

Area of a sector = (θ/360) × πr², where θ is the central angle in degrees.

Front

What is the relationship between the radius and the diameter of a circle?

Back

Diameter = 2 × Radius.

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 the central angle of a full circle?

Back

The central angle of a full circle is 360 degrees.

Front

How do you find the radius if you know the area of a circle?

Back

Radius = √(Area/π).

Front

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

Back

Area = π(5)² = 25π square inches.

Front

What is the area of a sector with a radius of 4 inches and a central angle of 90 degrees?

Back

Area = (90/360) × π(4)² = 4π square inches.

Front

What is the formula for the circumference of a circle?

Back

Circumference = 2πr, where r is the radius.