Can someone please Caplin how I do this?

If kn = 9 cm, mn = 21 cm, rs = 42 cm, and ps = 18 cm, what is the scale factor of figure klmn to figure pqrs?

Ben bowled 124 and 188 in his first two games. what must he bowl in his third game to have an average of at least 160?

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 .