Ineed on 21 can you show your work

Which statement explains how you could use coordinate geometry to prove that quadrilateral abcd is a parallelogram? -5 -4 -3 -2 -1 t 1 2 3 4 prove that all sides are congruent and have slopes that are opposite reciprocals prove that segments ad and ab are congruent and parallel prove that opposite sides are congruent and have equal slopes prove that segments bc and cd are congruent and parallel

The holiday party will cost $160 if 8 people attend. if there are 40 people who attend the party, how much will the holiday party cost

What is the similarity ratio of a cube with volume 729m^3 to a cube with volume 3375 m^3