The angle of elevation to the top of a 30 story skyscraper is measured to be 3 degrees from a point on the ground 2,000 feet from the building. what is the height of the skyscraper to the nearest hundreth foot?

You have an angle of elevation of 3 degrees and you're 2000 ft from base of 30 story building. 
Draw a picture of this. Then tan(3) = ht of bldg/2000 
I get a height of 104.82 ft rounded to 2 dp. 

5. Ok. use the Pythagorean Theorem here to find the hypotenuse of the right triangle 
hypt = sqrt(50^2 + 9^2) 
Now sine of the angle of elevation is 50/hypt. = 0.984 or 0.98 to 2 dp.