Area and circumference

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 formula for the circumference of a circle?

Back

Circumference = 2πr, where r is the radius of the circle.

Front

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

Back

Radius can be found using the formula r = √(Area/π).

Front

What is an arc in a circle?

Back

An arc is a portion of the circumference of a circle.

Front

How do you calculate the length of an arc?

Back

Arc Length = (θ/360) × 2πr, where θ is the central angle in degrees.

Front

What is a sector of a circle?

Back

A sector is a region enclosed by two radii and the arc between them.

Front

How do you find the area of a sector?

Back

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

Front

What is the relationship between the radius and 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 value of π (pi) approximately?

Back

π is approximately 3.14.