A garbage can that is the shape of a rectangular prism is 10 inches long, 3 inches wide and 9 inches tall. To the nearest tenth, what is the approximate length of its longest diagonal?
Use Pythagoras's Theorem:
Let the diagonal ==D
D^2 ==10^2 + 9^2
D^2==181 Take the sqrt of both sides
D ==Sqrt(181) ==13.4536 ==~13.5 inches - longest diagonal.