Please help with this math

Points a, b, and c form a triangle. complete the statements to prove that the sum of the interior angles of triangle abc is 180

A3-dimensional figure has a square base and 4 lateral faces that meet at a point. explain the difference between the cross sections when a slice is made perpendicular to the base through the vertex, and when a slice is made perpendicular to the base and not through the vertex

Y= 4x + 3 y = - 1 4 x - 5 what is the best description for the lines represented by the equations?