Maria sold 50 books, or 40% of her book collection at a yard sale. How many books were in Maria's collection?

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

Nikolas calculated the volume of the prism. his work is shown below.

If tan2a=cot(a+60), find the value of a, where 2a is an acute angle