Equilateral triangle vs circle

Find the area of an equilateral triangle inscribed in a circle of radius r = 9 cm. What percentage of the circle area does it occupy?

Correct answer:

S =  105.2221 cm2
p =  41.3497 %

Step-by-step explanation:

r=9 cm  a=3/3 r=3/3 9=9 3 cm15.5885 cm  S=43 a2=43 15.58852=105.2221 cm2
S1=π r2=3.1416 92254.469 cm2  p=100 S1S=100 254.469105.2221=41.3497%

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See also our trigonometric triangle calculator.

We encourage you to watch this tutorial video on this math problem: video1   video2

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