Question

in triangle ABC a=2,b=3,c=4then cosA=??
help me

Answer 1

Hey friend,


Here is your answer,

Given : a = 2, b = 3 and c = 4
Since, cos (A) = (b^2 + c^2 - a^2)/2bc (cosine rule)

Therefore,
cos (A) = (3^2 + 4^2 - 2^2)/2(3 × 4)
cos (A) = (9 + 16 - 4)/24
cos (A) = 21/24
cos (A) = 7/8 (ans)


Hope it helps you.
Thank you.