There is a problem I don't know how to solve, only that you are going to use the Pythagorean theorem twice.
From a house, there are two small roads to a bigger main road. The two roads are 1 and 2 km. The distance along the main road between the two road's connections with it is 1.5 km. You want to plan for a new road from the main road to the house. You want the new road to become as short as possible. How long will this road be?
Answer: 0,97 km