Point A is on the line y+3x=2 and is equidistant from points B and C, both of which lie on the line y=1/3x+8. D is on the intersection of both lines. Prove that y+3x=2 bisects BC.
Two triangles are similar.the lengths of the sides of the smaller triangle are 4,6,7. The longer side of the larger triangle is 21. What is the perimeter of the larger triangle?