arc length and sector area

Front

What is the formula for the area of a sector?

Back

Area = (θ/360) × πr², where θ is the angle in degrees and r is the radius.

Front

How do you calculate the arc length of a circle?

Back

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

Front

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

Back

Radius = Diameter / 2.

Front

If a pie has a diameter of 20 cm, what is its radius?

Back

Radius = 20 cm / 2 = 10 cm.

Front

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

Back

Area = πr² = π(10)² = 100π cm².

Front

What is the area of a sector that represents one fourth of a circle with a radius of 10 cm?

Back

Area = (90/360) × π(10)² = 25π cm².

Front

How do you find the area of the remaining sector if one fourth is taken?

Back

Remaining Area = Total Area - Area of Taken Sector.

Front

What is the formula for the area of an annulus?

Back

Area = π(R² - r²), where R is the outer radius and r is the inner radius.

Front

If the outer radius of an annulus is 8 inches and the inner radius is 5 inches, what is the area?

Back

Area = π(8² - 5²) = π(64 - 25) = 39π sq. in.

Front

What is the measure of a minor arc in a circle?

Back

The measure of a minor arc is equal to the central angle that subtends it.