I think it’s Tuesday afternoon. Sorry if I’m wrong!
Sin = opposite / hypotenuse
cos = adjacent / hypotenuse
using pythagoras theorem =
adjacent = 5^2-3^2
= 16
= square root 16
=4
cos x = 4/5
Answer:

Step-by-step explanation:
Given the expression

solving the expression



so the expression becomes


Thus,

Step-by-step
measure angle 1 is corresponding to measure angle 5
measure angle 5= measure angle 1= 71*
measure angle 5 + measure angle 8 = 180*
71*+ measure angle 8=180*
measure angle 8=109