Arithmetic sequence for 8 11 14 17 expression

Given that de, df, and ef are midsegments of △abc, and de=3.2 feet, ef=4 feet, and df=2.4 feet, the perimeter of △abc is .

Describe the relationship between the angles of similar triangles and the sides of similar triangles

Find the value of p for which the polynomial 3x^3 -x^2 + px +1 is exactly divisible by x-1, hence factorise the polynomial