Answer:
they are talking about the congruent sides of the figures.
Explanation:
both are the same triangle, just rotated a little differently... image you rotated them to look the same direction.... angles cd would look like the same angles as JL. same with CE and JM. just imagine the triangles are facing the same direction and then match up the same looking angle letters....
im sorry, it's hard to explain over writting..... :l