Answer: angle S = 33°
Step-by-step explanation:
We would apply the law of Cosines which is expressed as
a² = b² + c² - 2abCosA
Where a,b and c are the length of each side of the triangle and A is the angle corresponding to a. Likening the expression to the given triangle, it becomes
QR² = QS² + RS² - 2(QS × RS)CosS
10² = 17² + 18² - 2(17 × 18)CosS
100 = 289 + 324 - 2(306)CosS
100 = 613 - 612CosS
612CosS = 613 - 100
612CosS = 513
CosS = 513/612
CosS = 0.8382
S = Cos^- 1(0.8382)
S = 33° to the nearest whole degree
