For this case what we must do is use the cosine theorem to solve the problem. We have then: [tex]c ^ 2 = a ^ 2 + b ^ 2 - 2abcos (x)
[/tex] Where, a, b, c: are the sides of the triangle. x: is the angle between the sides a and b of the triangle. Substituting values we have: [tex]c ^ 2 = 90 ^ 2 + 75 ^ 2 - 2 (90) (75) cos (85)
[/tex] Clearing c we have: [tex]c = \sqrt{90 ^ 2 + 75 ^ 2 - 2 (90) (75) cos (85)} [/tex] Answer: option 1 [tex]c = \sqrt{90 ^ 2 + 75 ^ 2 - 2 (90) (75) cos (85)} [/tex]
