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]
