a) You have shown 3 pairs of corresponding sides, and no corresponding points. You could mark the upper left point on each figure, for example, as your corresponding points.
b) It is convenient to choose a dimension that is 1 unit in the smaller figure and find the corresponding measure in the larger one. You could use, for example, the lower left horizontal line segment, which is 1 unit long in the smaller figure and 4 units long in the larger figure. This ratio tells you ...
smaller/larger = 1/4