Math 100 points ill give brainliest as well

Two sides of a triangle mesure 20cm and 30cm. what is the measure of the third side

If, while training for a marathon, you ran 60 miles in 2/3 months, how many miles did you run each month? (assume you ran the same amount each month) write your answer as a whole number, proper fraction, or mixed number in simplest form. you ran __ miles each month.

Which describes the difference between the graph of f(x)=x^2 and g(x)=-(x^2-2)