Answer: 9.19 ft
Step-by-step explanation:
Hi, since the situation forms a right triangle (see attachment) we have to apply the next trigonometric function.
Sin α = opposite side / hypotenuse
Where α is the angle of elevation of the ladder to the ground, the hypotenuse is the longest side of the triangle (in this case is the length of the ladder), and the opposite side (x) is the height of the top of the ladder above the ground.
Replacing with the values given:
Sin 45 = x/ 13
Solving for x
sin45 (13) =x
x= 9.19 ft
Feel free to ask for more if needed or if you did not understand something.
