Calculate the length of PR. Give your answer correct to 3 significant figures (Diagram displayed on whiteboard)

In order to work out the unknown length of the triangle side PR, we first must identify which trigonometry equation to use. The digram gives us three values- 1 side and 2 angles. We know the hypotenuse (the longest side) is 17.6 cm long , angle P is 35 degrees, and angle R is 90 degrees. From the diagram, we also know that angle P is the angle of the "Opposite" side, and so the line PR is the "Adjacent" side. Given these values we can work out which equation is best to use. Using the mnemonic SOH-CAH-TOA, we can choose 'CAH'. This means we will use cosine in our equation. Thus, inputting the numbers given in the question into the equation 'Cos(x degrees) = Adjacent/ Hypotenuse', we get the following: Cos(35) = A/17.6. In order to work out A, we must rearrange the equation, which involves moving the hypotenuse value from the right side over to the left side of the equation. Once that is done we get the following equation: 17.6Cos(35) = A. Inputting that equation into the calculator gives us the answer of 14.4170783841. Nonetheless, the question asks that we give the answer correct to 3 significant figures, and so the the length of PR is 14.4cm.