00:04
Man is standing on the roof of a building 63 feet high, looks down to the building next door, and finds that the angle of depression to the roof of the building is 34 .9 degrees.
00:27
While the angle of depression from the roof of this building to the bottom of the building is 63 .5 degrees.
00:44
How tall is the building? we can figure out how tall the building is by there's there could be different methods, but we've got a horizontal here on the ground and we would know that this would be 63 .5 degrees as well.
01:17
So what 90 minus 63 .5 is 26 .5 degrees inside of our triangle here which i think just to clean up i'm going to recreate over here so we want to find x this is going to be 26 .5 degrees we can find since this is going to be a right angle as well we can find how much would just be inside if we if we took 90 and subtracted 34 .9 and the 26 .5 because this is 26 .5 here by alternate interior angles 90 minus 34 .9 minus 26 .5 meets 28 .6 degrees and then from 180 we can subtract the 28 .6 and the 26 .5 we've been 124 .9.
03:01
Now we can find what i'm going to call why with a right triangle triangle triangle.
03:09
Relationship using the 63 .5 degrees, 63, and y.
03:23
So that's opposite and hypotenuse.
03:25
We can say that the sign of 63 .5 degrees is equal to the opposite 63 over the hypotenuse y.
03:33
Multiply y to both sides and then divide by the sign of 63 .5 and we'll have the hypotenuse.
03:46
So in degree mode, 63 divided by a sign of 6 .6 .3.
03:50
63 .5 is 70 .4.
04:00
Now we can use the law of cos, usually the law of signs.
04:06
We can say that the sign of an angle over its opposite side is in proportion to the sign of an angle over its opposite side.
04:19
Cross multiply and then divide by the sign of 124 .9.
04:30
And we have x solved 4.
04:32
So 70 .4, sign 28 .6...