How to find the hypotenuse of a right triangle khan academy?

What is the number 321,000,000 in scientific notation? also what is the number? ?

Just tell me how to set up the equation.

Which shows the correct lengths of side c in both scales? scale 1: 45 m; scale 2: 60 m scale 1: 60 m; scale 2: 45 m scale 1: 36 m; scale 2: 27 m scale 1: 27 m; scale 2: 36 m mark this and return save and exit