How to work the problems out and the answers to 3 of my homework questions?

Which statement is true 1.the pythagorean theorem can be used to find the missing side of any triangle 2.the pythagorean theorem can be used to find the missing side of any polygon 3. the pythagorean theorem can be used to find the missing side of any right triangle 4.the pythagorean theorem can be used to find the missing side of any isosceles triangle

Runner ran 1 4/5 miles on monday and 6 3/10 on tuesday. how many times her monday’s distance was her tuesdays distance

Select the point that is a solution to the system of inequalities. y< =-x+3 y=x^(2)-3x