Answer:
5 √ 10 + 2 √ 5 ft high
Step-by-step explanation:Explanation:
Let h be the height to which latter of length of 20 ft reach then using Sine formula in right triangle with hypotenuse 20 & vertical leg h & opposite acute angle 0 = 72∘ sin θ =h 20 sin 72∘= h 20
h
=
20
sin
(
90
∘
−
18
∘
)
=
20
cos
18
∘
=
20
(
√
10
+
2
√
5
4
)
=
5
√
10
+
2
√
5
