That would be true because the adjacent side to B is 4 and the hypotenuse is 5 and the formula for cos b is adjacent/hypotenuse
Hope this helps!
Total area of the ends: 2(2")(6") = 24 in^2
Total area of the sides: 2(2")(9") = 36 in^2
Are of the bottom : 1(6")(9") = 54 in^2
Total surface area to be covered = (24+36+54) in^2
Answer: x = 20 degree
3x = 3×20 which is 60 degree
And the other one is 100 degree
Add all the number 100+60+20 degree is 180 degree
