Identifying corresponding parts in similar figures isn't so bad, but you have to know what you're looking for. This tutorial does a great job of explaining the corresponding parts of similar figures! Take a look!
Use similar triangles to explain why the slope m is the same between any two distinct points on a non-vertical line in the coordinate plane; derive the equation y = mx for a line through the origin and the equation y = mx + b for a line intercepting the vertical axis at b.
Looking at two figures that are the same shape and have the same angle measurements? You have similar figures! Learn all about it in this tutorial!
Understand that a two-dimensional figure is congruent to another if the second can be obtained from the first by a sequence of rotations, reflections, and translations; given two congruent figures, describe a sequence that exhibits the congruence between them.
Trying to find a missing measurement on similar figures? Make ratios from corresponding sides and set up a proportion! Solve the proportion to get your missing measurement. Figure out how to do all that by watching this tutorial!