Elliott is standing at the top of a store escalator that leads to the ground floor below. The angle of depression from the top o
f the escalator to the floor is 39.81°, and the escalator is 15.5 feet long. How far is the top of the escalator from the ground floor? Round your answer to the nearest foot.
The described situation can be represented by a right triangle, where the base is the ground floor, the hypotenuse is the escalator and the height is the distance from the top of the escalator to the ground floor (the opposite side to the given angle).
In a right triangle, the trigonometric functions can be expressed as:
where is one of the angles, OS and AS are the opposite side and the adjacent side respectively, and H is the hypotenuse.
In this case, we want to know how long is the opposite leg, so we're going to use the sin:
So, the top of the escalator is approximately 10 feet from the ground floor.
The top of the escalator is 10 ft from the ground floor
Step-by-step explanation:
we know that
The function sine of angle of 39.81 degrees is equal to divide the opposite side to the angle of 39.81 degrees (distance of the top of the escalator from the ground floor) by the hypotenuse (15.5 ft)
so
Let
h ------> distance of the top of the escalator from the ground floor
The minimum and maximum value of over all real are and , respectively. Hence, the maximum and minimum value of would be:
Maximum: .
Minimum: .
The midline equation of a sine wave is a horizontal line that is right in the middle of maximum and minimum -values of that sine wave. In the sine wave in this question, the average of the maximum and minimum -values is . Hence, the midline equation of this sine wave would be .