Circle Length of Arc and Area of Sector

In circle O, the radius is 4, and the measure of minor arc AB is 120 degrees. Find the length of minor arc AB to the nearest integer.

• 5

• 9

• 8

• 6

Find the arc length.  Leave your answer in terms of π.

• 7/4π

• 7/2π

• 1/8π

• 45π

Find the area of the shaded sector of circle O.  The radius is 6 inches and the central angle is 100°.  Express answer to the nearest tenth of a square inch.

• 9.2 sq. in.

• 10.5 sq. in.

• 31.4 sq. in.

• 38.2 sq. in.

Find the area of the dark blue sector shown at the left.  The radius of the circle is 4 units and the length of the arc (the curved edge of the sector) measures 7.85 units.  Express answer to thenearest tenth of a square unit.

• 0.3 square units

• 15.7 square units

• 19.7 square units

• 50.3 square units

How does the process for finding the arc length differ from the process for finding the sector area?

• The arc length is a degree while the sector area is labeled in square units.

• The arc length uses π while the sector area does not always use π.

• The arc length and sector area are always equal.

• The arc length requires using the circumference while sector area requires the circle area formula.

The diagram shows a sector of a circle of radius 4 units, formed from an angle of size 135°.

Find the length of the arc rounded to two decimal places.

Mathematical Equivalence

ON

Match the answers to the following problems.

• Problem 1

• Problem 3

• Problem 4

• Problem 2

How is the process for finding the arc length different from the process for finding the sector area?

• The arc length is a degree while the sector area is labeled in square units.

• The arc length uses π while the sector area does not always use π.

• The arc length and sector area are always equal.

• The arc length requires using the circumference while sector area requires the circle area formula.

Find the length of the bold arc.

• 61.3ft

• 20.4ft

• 7351.3ft

• 22,068ft

What is the arc length of minor arc AB?

• 5.23

• 103

• 33.33

• 50