How would the distance formula be used in real life?

One example I can think of is to measure the direct distance between two locations. suppose A lives on the intersection of 30th avenue and 50th street, B lives on 70th avenue and 80th avenue, the distance between them would be the square root of [ (70-30) ^2 + (80-50) ^2) ], which is 50, so the straight-line distance between the two places are 50 blocks.