The recommended angle for a firefighting ladder is 75 degrees. When a 110-foot ladder is put up against a building at this angle, the base of the ladder is about 28 feet from the building. The base of the ladder is 8 feet above the ground. How high on the building will the ladder reach?

Answer :

cryssatemp

Answer: 114.37 ft

Step-by-step explanation:

If we model this situation as a right triangle, where the hypotenuse is the length of the ladder ([tex]110 ft[/tex]), the opposite leg is the height the ladder will reach [tex]h[/tex], and the adjacent leg is the distance between the base of the ladder and the building ([tex]28 ft[/tex]); we have two options:

1) Using trigonometric functions, since we are given the angle [tex]\theta=75\°[/tex]

2) Using the Pithagorean Theorem

Any of the options will give a similiar result. So, let's choose the Pithagorean Theorem:

[tex](hypotenuse)^{2}=(opposite-leg)^{2}+(adjacent-leg)^{2}[/tex]

[tex](110 ft)^{2}=(h)^{2}+(28 ft)^{2}[/tex]

Isolating [tex]h[/tex]:

[tex]h=\sqrt{(110 ft)^{2}-(28 ft)^{2}}[/tex]

[tex]h=106.37 ft[/tex]

Adding to this height the extra height of [tex]8 ft[/tex] (since the base of the ladder is at this distance above the ground, perhaps held by a firefighter truck):

[tex]h=106.37 ft+8 ft=114.37 ft[/tex] This is the height the ladder will reach

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