Answer:
The height (in feet) at which the laser will impact the wall is 6.75 feet
Step-by-step explanation:
The given parameters are;
The height from which the laser beam operator is holding the laser = 9 feet
The horizontal distance away from the pointer the beam is reflected = 8 feet
Given that we have;
![f(x) = \dfrac{9}{8} \times \left | x - 8\right | = y](https://tex.z-dn.net/?f=f%28x%29%20%3D%20%5Cdfrac%7B9%7D%7B8%7D%20%5Ctimes%20%5Cleft%20%7C%20x%20-%208%5Cright%20%7C%20%3D%20y)
When x = 8, the point of reflection, the height, f(x) is given as follows;
![f(x) = \dfrac{9}{8} \times \left | 8 - 8\right | = 0](https://tex.z-dn.net/?f=f%28x%29%20%3D%20%5Cdfrac%7B9%7D%7B8%7D%20%5Ctimes%20%5Cleft%20%7C%208%20-%208%5Cright%20%7C%20%3D%200)
When x = 7, the point of reflection, the height, f(x) is given as follows;
![f(x) = \dfrac{9}{8} \times \left | 7 - 8\right | = \dfrac{9}{8}](https://tex.z-dn.net/?f=f%28x%29%20%3D%20%5Cdfrac%7B9%7D%7B8%7D%20%5Ctimes%20%5Cleft%20%7C%207%20-%208%5Cright%20%7C%20%3D%20%5Cdfrac%7B9%7D%7B8%7D)
Therefore, given that the point of reflection is at an elevation of 0 relative to the 9 feet of the laser source (pointer), by tan rule, we have;
![tan(\theta) = \dfrac{Opposite \ side}{Adjacent \ side} =\dfrac{9}{8} = \dfrac{h}{7}](https://tex.z-dn.net/?f=tan%28%5Ctheta%29%20%3D%20%5Cdfrac%7BOpposite%20%5C%20side%7D%7BAdjacent%20%5C%20side%7D%20%3D%5Cdfrac%7B9%7D%7B8%7D%20%3D%20%5Cdfrac%7Bh%7D%7B7%7D)
Where;
h = The height at which the laser meets the wall
![h = \dfrac{9 \times 7}{8} =7.875](https://tex.z-dn.net/?f=h%20%3D%20%5Cdfrac%7B9%20%5Ctimes%20%207%7D%7B8%7D%20%3D7.875)
Given that the wall the laser meets is at the point x with elevation 9/8, the height, y, at which the laser meets the wall is therefore;
![y = \dfrac{9 \times 7}{8} - \dfrac{9}{8} = \dfrac{54}{8} = 6.75 \ feet](https://tex.z-dn.net/?f=y%20%3D%20%5Cdfrac%7B9%20%5Ctimes%20%207%7D%7B8%7D%20-%20%5Cdfrac%7B9%7D%7B8%7D%20%3D%20%5Cdfrac%7B54%7D%7B8%7D%20%3D%206.75%20%5C%20feet)
The height (in feet) at which the laser will impact the wall = 6.75 feet.