Orange shape of a size 5.655 cm^2 is making one fifth of the area of a cricle and |PR| = 1.4 cm. Calculate the area of the blue circle segment using following rules: 1. Every result round up to 3 signifficant digits 2. Use Pi button on a calculator or (3.141592654)
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Since we know that orange shape is making one fifth of the area of a cricle, we can calculate its radius: S E O P = 5 1 × S C S C = 5 × 5 . 6 5 5 = 2 8 . 2 7 4 c m 2 = 3 c m 2 S C = π × r 1 2 ⇒ r 1 = π S C = π 2 8 . 2 7 4 \buildrel . We can notice that: r 1 = b c a = r 1 − ∣ P R ∣ = 3 − 1 . 4 = 1 . 6 c m By using Pythagorean theorem, we can calculate a height from the point C : v c = b 2 − c a 2 = 3 2 − 1 . 6 2 = 2 . 5 3 8 c m By using Euclid's formula, we can calculate 2nd part of the side c : v c 2 = c a × c b ⇒ c b = c a v c 2 = 1 . 6 2 . 5 3 8 2 = 4 . 0 2 6 c m Via trigonometric formula for sin , we can calculate angle beta : sin ( β ) = c b ⇒ β = arcsin ( c b ) = arcsin ( 4 . 0 2 6 + 1 . 6 3 ) = 3 2 . 2 We can tell, that: β = δ Where delta is XBY angle and also for the radius of a 2nd circle: r 2 = c b Our last step involves a formula for a circle segment: S = 2 1 × r 2 2 ( 1 8 0 π × δ − sin ( δ ) ) = 2 1 × 4 . 0 2 6 2 ( 1 8 0 π × 3 2 . 2 − sin ( 3 2 . 2 ) ) = 0 . 2 3 6 c m 2