A triangle has sides of length 5 ft, 9 ft, and 13 ft.
What is the measure of the angle opposite the side that is 9 ft long?
THERE IS NO PIC
30°
41°
60°
87°
See the attached image of what this could look like. Based on the image a = 9 b = 5 c = 13 We need to find angle A as its opposite the length of 9 units (a = BC = 9)
Use the law of cosines to find the angle A a^2 = b^2 + c^2 - 2*b*c*cos(A) 9^2 = 5^2 + 13^2 - 2*5*13*cos(A) 81 = 25 + 169 - 130*cos(A) 81 = 194 - 130*cos(A) 81 - 194 = -130*cos(A) -113 = -130*cos(A) -130*cos(A) = -113 130*cos(A) = 113 cos(A) = 113/130 A = arccos(113/130) A = 29.6306 Rounding to the nearest whole number, the answer is 30 degrees
