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Trigonometry!!!!!!!!!!!!!

+2 votes
If the tangent of an acute angle is 1/4, what is the cosine of that angle?
asked Feb 16, 2013 in TRIGONOMETRY by andrew Scholar

1 Answer

+2 votes

Tangent = opposite side of right triangle divided by adjacent side of right triangle.

cosine = adjacent side of right triangle divided by hypotenuse.

You were given tan(x) = 1/4, which tells me that the opposite side is 1 and the adjacent side is 4.

We use the Pythagorean Theorem from geometry to find the hypotenuse.

Let A = hypotenuse.

(1)2 + (4)2 = A2

1 + 16 = A2

A2 = 17

Taking the square root of both sides, we get A = √17.

Like I said before, cosine = adjacent side of right triangle divided by hypotenuse.

Then cos(x) = 4/√17.

answered Feb 16, 2013 by britally Apprentice

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