The Exact Value of sin 72 degrees.

The exact value of sin 72deg = √(10+2√5)/4 can be solve by using the Pythagorean Theorem Relations formula sin theta = √[1 - (cos theta)^2], where theta = 72deg, or sin 72 deg = √[1 - (cos 72deg)^2]. Substitute the exact value of cos 72deg = (√5-1)/4 to the formula, in which I've already solved above and included in this playlist. Evaluate and simplify.

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