00:01
So for this question, the angle of elevation to the top of a tower from some point a is 17 .5 degrees.
00:21
Like so.
00:23
So this is our tower here.
00:30
And so this is at point a.
00:32
So this angle here is 17 .5 degrees.
00:41
And then we have some point b, which is 35 .6 feet closer to.
00:45
Of the tower.
00:47
So this distance here is 36 .9 feet.
00:52
And this time the angle is, let me see if i can draw a bit better.
00:57
The angle is, there we go, the angle is 22 .5 degrees.
01:08
We need to find what the angle, so what the height of the tower is.
01:16
Well, we can maybe do some simple trick to work this up.
01:19
If this is 22 .5 degrees, then this angle here must be 180 minus 22 .5, which is 157 .5.
01:32
And therefore, this angle here is 180 minus 15 .5 which is just 5 degrees.
01:42
And so this angle here is 100 .5.
01:48
180 minus 90 minus 22 .5, which leaves us with 67 .5 degrees.
01:57
And so what do we know now? well, we know that we can use the sign rule for some of this...
