Is there a formula for the following:

Say a fence cuts across the (right angle) NE corner of a yard (the north line is 51 feet long, the east line is 124 feet long and the fence is 134 feet long; the fence needs to be moved exactly 10 feet further (SW) from where it is. How long do each of the three sides of the triangle need to be? (the north line, the east line and the fence)

Thanks!