For the first one, we can use the tangent to solve. We know an angle and an adjacent side to the angle. We are looking for the opposite side. So......
tan(50) = opposite/100 multiply both sides by 100
100tan(50) = opposite ≈ 119.18 m
For the second one, we are looking for the ladder length (the hypoteneuse). We know an angle and the opposite side. The thing that relates all three of these is the sine. So we have..
sin(60) = 15/x where x is the hypoteneuse (the ladder length).....rearranging, we have...
x = 15/sin(60) ≈ 17.32 m
And that's it !!!