Warm-UP 14 cm • Find the diameter or radius: a. r = 7 cm; d = ░ b. d = 5 in; r = ░ c. r = 4.2 ft; d = ░ • Simplify (round to the nearest tenth): a. π•20= b. 2•π•7= 2.5 in 8.4 ft 62.8 44.0
Circumference 6.7 Arc Length
Circumference Circumference The distance around a circle
1. 2. Find the circumference to the nearest tenth. 33 m 14.3 in. C = 89.8 in C = 103.7 m
Exact Measure Circumference EX: What is the exact measure of the circumference? Writing your answer in terms of π 14.3 in.
ON YOUR OWN: What is the exact measure of the circumference? 33 m
3. The circumference of a half dollar is about 96 millimeters. Find the diameter of the coin to the nearest tenth. d ≈ 30.6 mm
4. A circular flower garden has a circumference of 20 feet. Find the radius of the garden to the nearest hundredth. r ≈ 3.18 ft
GUIDED PRACTICE 26.9 Simplify (Round to the nearest tenth): 1. 2. 3. 6.3 23.6
Arc Length piece portion a fraction of the circumference of a circle part section
Arc Length Corollary the ratio of the length of an arc to the circumference is equal to the ratio of the measure of the arc to 360º * *
Guided Practice Complete How Do You Find Arc Length?
A Example 1 90º B 15 ft Find the length of arc AB to the nearest hundredth. A 23.55 ft
Example 2 A 40º B 6 m Find the length of arc AB to the nearest hundredth. A 4.19 m
A 18.84 m Example 3 B 9 m Find the measure of arc AB to the nearest degree. mAB = 120º
A Example 4 1.57 ft 45º B N Find the radius of circle N to the nearest foot. r ≈2 ft
A Example 5 41.87 cm Q 200º B Find the circumference of circle Q. C ≈75.37 cm
Homework p. 226 (1-10, 17-19) Show ALL Work for Credit!!