In a right angled triangle, we can use SOH CAH TOA . assuming you are confident with Pythagoras, your first step is to find the hypotenuse(the longest side of the triangle). the second step is to set out your equations( one of the following depending on which sides you have available). 1)singAngle = opposite/hyp locate your angle, the side that it facing it( not touching it directly) will be your opposite. then locate your hyp. enter all values into the equation above. to find the actual value you will need to find the inverse of sine, thus you will (assuming you have a calculator) do shift sin , and on the screen you will see sin^-1 which is the inverse of sin. type in shift sin (opp/hyp) and press equals to get your angle. 2) Cosineangle= adjacent/hyp adjacent side is the side that is touching the angle BUT not the longest side of the triangle( thats the hyp). do as above. using shift cos to get cos^-1 3) same as the other two except you use tanangle=opp/adjacent then shift tan to get tan^-1