M20 | Maths Made Easy


Question: Find the size of the angle marked q to 1 d.p.


Answer: The two sides we’re concerned with are the hypotenuse and the opposite (to the angle) – O and H. Therefore, we want the ‘SOH’ part of ‘SOHCAHTOA’, so will be using sin. We have O=13,H=15, and the angle is q, so we get


Then, to get q, we have to apply the inverse sin function: \sin^{-1} to both sides. It cancels out the sin on the left-hand side, and we get


Finally, putting this into the calculator we get

q=60.0735...=60.1\degree\text{ (1dp)}