If sin theta = x/y . Then prove that tan theta = x/ under root y^2-x^2​

Which of the following statements is not true? a.parallel lines are lines in the same plane that never intersect. b.congruent figures have the same shape and same size angles and sides. c.similar figures must have the same shape and the same size. d.a rotation is when you turn a figure around a certain point.

Ateacher wanted to buy a chair, a bookshelf, two tables and a desk. she spent $900 for all five items and the chair and the desk combined 70% of her total. if the bookshelf cost $50, how much did each of the tables cost?

Bob paid $3 less than tim at a local pizza parlor. together they spent $7.80. how much did bob pay for pizza?