Can someone explain me to me how to solve this

Solve these problems: 1.what is the perimeter of an equilateral triangle with sides measuring 6cm? 2. a regular pentagon has sides measuring 3.2 cm. what is its perimeter? 3. a regular decagon has sides of 3.5mm . what is it’s perimeter? 4. a regular octagon has a perimeter of 64cm. what is the length of one of the sides? 5. a regular hexagon has a perimeter of 72mm . what is the length of one of the sides? 6. what is the perimeter of a rhombus with sides measuring 11m?

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.

Parallelogram rstu is a rhombus. m∠r = 120° what is m∠t = 120 (what is m∠rsu? )