1. Areas of Plane Figures 11-5 Circumferences and Areas of Circles
Circumference of a circle: C = 2πr or C = πd
Area of a circle: A = πr 2
Unless specified otherwise leave answers in terms of π.

2. Examples
If 6 oz of dough are needed to make an 8-in. pizza, how much dough will be needed to make a 16-in. pizza of the same thickness. (Hint: compare the areas of the pizza tops.)
Answer: 24 oz
Find the circumference and area of a circle with radius 25.
Answer: 50π, 625π

3. Practice Assignments CW: p. 447 1-12 even
HW: p , 6, 10, 14, 17, 18, 24, ; Section 11.6 Worksheet