Date:
Chapter 10.1 and 11.3: Circumference and Area of Circles
Objective Do Now: Pg. R3 #1-4, 6
Example 1: Find Circumference
A. CROP CIRCLES A series of crop circles was discovered in Alberta, Canada, on September 4, 1999.
The largest of the three circles had a radius of 30 feet. Find its circumference.
B. The Unisphere is a giant steel globe that sits in Flushing Meadows-Corona Park in Queens, New
York. It has a diameter of 120 feet. Find its circumference.
Example 2: Find Radius and Diameter
A. Find the diameter and the radius of a circle to the nearest hundredth if the circumference of the
circle is 65.4 feet.
B. Find the radius of a circle to the nearest hundredth if its circumference is 16.8 meters.
Example 3: Find Arc Length
A. Find the length of DA.
B. Find the length of DA.
C. Find the length of DA.
D. Find the length of JL
E. Find the length of JL
Example 4: Find Area of a Circle
A. An outdoor accessories company manufactures circular covers for outdoor umbrellas. If the
cover is 8 inches longer than the umbrella on each side, find the area of the cover in square
inches.
B. A swimming pool company manufactures circular covers for above ground pools. If the cover is
1 foot longer than the pool on each side, find the area of the cover.
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Example 5: Use Area to find radius and diameter
A. Find the radius of a circle with an area of 58 square inches.
B. Find the radius of a circle with an area of 45 square inches.
Example 6: Find Area of a Sector
A. A pie has a diameter of 9 inches and is cut into 10 congruent slices. What is the area of one slice
to the nearest hundredth?
B. A pizza has a diameter of 14 inches and is cut into 8 congruent slices. What is the area of one
slice.
C. Find the area of the sector.