Find the length of the hypotenuse of a right triangle whose legs have lengths 4 and 8

How is working backward similar to solving an equation?

You can ride your bike around your block 6 times and the whole neighborhood 5 times in 16 minutes. you can ride your bike around your block 3 times and the whole neighborhood 10 times in 23 minutes. how long does it take you to ride around the neighborhood?

The difference between the measures of two complementary angles is 14. find the measure of both angles.