11.3 Area of Circles, Sectors, Segments

Front

What is the formula for the area of a circle?

Back

A = πr², where A is the area and r is the radius.

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 a segment of a circle?

Back

A segment is the area of a circle that is 'cut off' from the rest of the circle by a chord.

Front

How do you find the area of a segment?

Back

Area of a segment = Area of the sector - Area of the triangle formed by the radii and the chord.

Front

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

Back

Diameter = 2 × Radius.

Front

What is the value of π (pi)?

Back

π is approximately 3.14, but it is an irrational number with an infinite number of decimal places.

Front

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

Back

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

Front

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

Back

A = π(5)² = 25π cm².

Front

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

Back

Area = (90/360) × π(4)² = (1/4) × 16π = 4π cm².