To find the answer we simply work out the equation.
cos (75) = 10/x
cos (75) * x = 10. Here, I simply multiplied both sides by x to move x to the left hand side of the equation.
x = 10 / cos (75) Here, I divided cos (75) on both sides to move cos (75) to the right hand side of the equation.
The cosine of 75 is 0.92175127, so, 10 / 0.92175127 = 10.8489137
