00:01
So let's draw for part a, let's draw this triangle we have on the right side.
00:08
We know that this angle is going to be 80 degrees because the inclination from the ground is 10.
00:14
And to stand straight up on the tower, it's going to have to equal 90.
00:17
So 90 minus 10 is 80.
00:18
This side is going to be 190 feet and this side is going to be 350 feet.
00:23
And in general, when we have a triangle side, the angle in between the two sides and the next side, we can solve this using the law of signs or the law of cosines.
00:34
Which here is going to tell us that this side here, c squared is going to be equal to 350 squared plus 190 squared minus 2 times 350 times, 190 times cosine of 80 degrees...