Question

A source of laser light sends rays AB and AC toward two opposite walls of a hall. The light rays strike the walls at points B and C, as shown below:
A source of laser light is at point A on the ground between two parallel walls. The walls are perpendicular to the ground. AB is a ray of light which strikes the wall on the left at point B. The length of AB is 60m.AC is a ray of light which strikes the wall on the right at point C which is 40m above the ground. The ray AB makes an angle of 60 degrees with the ground. The ray AC makes an angle of 45 degrees with the ground.

What is the distance between the walls?

80 m
140 m
70 m

Answer 1

Answer: 70m

Step-by-step explanation:

For wall from the left, we have a right triangle and hypotenuse is 60 and the adjacent leg is what we want to find. The angle is 60°

cos60 = x/60

1/2 = x /60

2x = 60

x = 30

For wall from the right, we have a right triangle and opposite leg is 40 and the adjacent leg is what we want to find. The angle is 45°

tan45 = 40/x

1 = 40/x

x = 40

As the distance between the walls is the sum of the bases of the triangles, 40 + 30 = 70 m

Answer 2

When drawn out, the answer becomes the sum of the bases of two triangles

Answer: 70 m