In right triangle ABC, angle B is 90 degrees. If tan C = 2.4. Find cos A. No caculator
If tan C = 2.4 then we can let AB = 2.4 and we can let BC = 1
So AC = sqrt ( 2.4^2 + 1^2) = sqrt ( 5.76 + 1) = sqrt ( 6.76) = 2.6
Cos A = BC / AC = 1 / 2.6 = 1 /( 26/10) = 10/26 = 5/13
