Hello!
We are going to need to use a trigonometric ratio for this. There are three of them - sin, cos, and tan. Sin: opposite / hypotenuse Cos: adjacent/hypotenuse Tan: opposite/adjacent
So here, we are given an angle. We are also given one side length. That side is opposite the angle, and we are trying to find the hypotenuse. Therefore, we use the ratio sine.
First, do sin(40). This'll give us the ratio of the side length of the opposite / the side length of the hypotenuse. sin (40) = 0.64278761.
Now, we know that the side length of the opposite / the side length of the hypotenuse = 0.64278761. We also know the side length of the opposite, or the length of highway 1: 5.6. Therefore, we know 5.6 / side length of the hypotenuse = 0.64278761.
Now, solve for the side length of the hypotenuse. I'll just be using h to represent it.
5.6 / h = 0.64278761
5.6 = 0.64278761h
5.6 / 0.64278761 = h
5.6 / 0.64278761 = h
h = 8.71205343 = about 8.7
Therefore, your answer is A.
Hope this helps!