Firstly when you read the question you should label the hypotenuse, adjacent and opposite sides on the triangle.
The 3 formulas that you will need in order to find a missing side are:
SOH: Sin = o/h
CAH: Cos = a/h
TOA: Tan = o/a
Find the length of side BC.
You are given the hypotenuse and you can label line AC as adjacent (its next to the angle) and you need to find the opposite line/BC.
Therefore you need to use the Sin (o/h) formula.
So press the sin button on your calculator and type the angle you have been given and press =
Sin(30 and that should equal 0.5
Then you need to multiply it by the length of the side you've been given.
0.5 x 7 = 3.5 and then line…