Find the circumference and area of a circle if 1) d = 14.5 cm 2) r = 21.4 cm
| September 9, 2021 | education
1) Given:
d = 14.5 cm;
Find: L =?
S =?
Solution:
L = 2 * Pi * r = d * Pi (circumference).
L = 14.5 * 3.14 = 45.53 (cm).
S = Pi * r ^ 2 (area of a circle).
Find the radius r = d / 2 = 14.5: 2 = 7.25 (cm).
Then S = 3.14 * (7.25) ^ 2 = 3.14 * 52.5625 = 165.04625 (sq. Cm).
Answer: L = 45.53 cm; S = 165.04625 sq. cm.
2) Given:
r = 21.4 cm;
Find: L =?
S =?
Solution:
L = 2 * Pi * r (circumference).
L = 2 * 3.14 * 21.4 = 134.392 (cm).
S = Pi * r ^ 2 (area of a circle).
S = 3.14 * (21.4) ^ 2 = 3.14 * 457.96 = 1437.9944 (sq. Cm).
Answer: L = 134.392 cm; S = 1437.9944 sq. cm.
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