Help, im failing math. i need to get this correct

Me complete this proof! prove that a quadrilateral is a square. me with the steps for this proof.

Find the missing variable for a parallelogram: a = latex: 28in^2 28 i n 2 h = b = 6.3 in (1in=2.54cm)

The mass of a marine organism, in pounds, p years after it is born is given by the polynomial function r(p) = -4p2 + 300p. find the mass when p = 20 years.