Question

I don't know how to do #86-#88. Any help?

Answer 1

86 and 87 utilize the Pythagorean theorem. Where those tangent lines meet the circle forms a right angle. So you have a side length of 6 and a hypotenuse of 22. So the missing side length is 21.16.  For 87, its the same thing, but you have the 2 legs but are missing the hypotenuse.