1.) First you have to find out the measure of all the angles of the triangle that the building ground and ladder form. 
One is 35 degrees, as said in the equation 
The one formed between the building and the ground is 90 degrees. 
The total of all degrees of a triangle is 180 
So..Add 35+90 for a total of 125 
Then subtract that from 180 
Your missing angle is 55 degrees 
Then you can make proportions by using the angle it's opposite side. 
We know that the bottom of the triangle is 8 ft, and the angle opposite this side is 55 degrees, so we have 8/55 
Then the hypotenuse [which is the side we're trying to find out, we'll call it x] is opposite the 90 degree angle, so we have x/90 
8/55=x/90 
Now cross multiply 
8*90=55x 
Simplify 
720=55x 
Divide both sides by 55 
x=13.09 ft