Question

How do I find CosA, SinA, and TanA for a given right triangle? The triangle has A, B, and C. There is no given degree, but since it is a right triangle it has to be 90 degrees. The numbers are 70, 12, and x (missing side).

70 inches = opposite side

12 feet = hypotenuse side

x = adjacent side


How do I find the missing adjacent side?

College Level Math: Math 114 for Liberal Arts Majors

Answer 1

Explanation:

First, convert feet to inches.

12ft = 144in

Use Pythagorean theorem to find the third side.

c² = a² + b²

144² = 70² + x²

x = √15836

x ≈ 125.8

Now use SOH CAH TOA to find the trigonometric values.

sine = opposite / hypotenuse

sin A = 125.8 / 144

sin A ≈ 0.874

cosine = adjacent / hypotenuse

cos A = 70 / 144

cos A ≈ 0.486

tangent = opposite / adjacent

tan A = 125.8 / 70

tan A ≈ 1.798