You and a friend stand back to back. you run 20 feet forward then 15 feet to the right. at the same time, your friend runs 16 feet forward then 12 feet to her right. she stops and hits you with a snowball. how far does your friend throw the snowball?

To get the distance the friend threw the ball to hit me will be given by Pythagorean theorem. 

From the figure below D is my position E is friend's position. The distance we are estimating is ED
ACE  and ADB are assumed to be right angles. 

c²=a²+b²
Thus the length of the hypotenuse made from the triangle movement I moved will be:
c²=20²+15²
c²=400+225
c²=625
c=25 ft

Length of the hypotenuse made by my friend will be:
c²=16²+12²
c²=256+144
c²=400
c=20 ft
The total distance the ball will be thrown will be:
20+25=45ft