Under what condition the composite function of any two function is an identity function?

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?

Right triangle abc has three sides with lengths ab= 119, bc = 169, ca= 120. find the value of cos c. hint: draw and label the triangle. the hypotenuse is always the longest.

Ineed ! if you answer wrong for points i will report you! but hurry this is timed!