Which pair of angles are vertical angles?

∠krc and ∠crh

∠kre and ∠ert

∠mrc and ∠krm

∠ert and ∠mrc

72 the length of a side of a triangle is 36. a line parallel to that side divides the triangle into two parts of equal area. find the length of the segment determined by the points of intersection between the line and the other two sides of the triangle.

Astudent showed the steps below while solving the inequality |x-4|< 1 by graphing.

The floor of a building consists of 3000 tiles which are rhombus shaped and each of it's diagonals are 45 cm and 30 cm in length. find the total cost of polishing the floor, if the cost per m² is rs. 4.