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Learn how to find the arc lengths and measures of different angles using formulas and substitution. Practice problems included.
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a. 60° a. = 2π(8) Arc length of AB 360° EXAMPLE 3 Find arc lengths Find the length of each red arc. SOLUTION ≈ 8.38 centimeters
b. 60° = b. Arc length of EF 2π(11) 360° EXAMPLE 3 Find arc lengths Find the length of each red arc. SOLUTION ≈ 11.52 centimeters
120° c. 2π(1) Arc length of GH = 360° c. EXAMPLE 3 Find arc lengths Find the length of each red arc. SOLUTION ≈ 23.04 centimeters
a. Circumference C of Z Arc length of XY a. m XY = 360° C 4.19 40° = 360° C 4.19 1 = 19 C EXAMPLE 4 Find arc lengths to find measures Find the indicated measure. SOLUTION 37.71 = C
b. m RS Arc length of RS m RS b. = 360° 2 r 44 m RS = 2 (15.28) 360° 44 = m RS 360° 2 (15.28) 165° m RS EXAMPLE 4 Find arc lengths to find measures Find the indicated measure. SOLUTION
3. Length ofPQ 75° (9) 5.89 yd Arc length of PQ= 360° for Examples 3 and 4 GUIDED PRACTICE Find the indicated measure.
4. Circumference of N Arc length of LM =m LM 360° C 61.26 = 270° 360° C 61.26 = 27 36 C for Examples 3 and 4 GUIDED PRACTICE 81.68 m = C
5. Radius of G Arc length of EF =m EF 360° C 10.5 = 150° 360° C 10.5 = 5 12 C for Examples 3 and 4 GUIDED PRACTICE 25.2 = C
C=2 r = 2 3.12 r 25.2 2 3.14 r r = 25.2 4.01 r The radius of G is about 4.01. for Examples 3 and 4 GUIDED PRACTICE Write a formula. Substitute Solve for r