How does the area of triangle rst compare to the area of triangle lmn? the area of △rst is 2 square units less than the area of △lmn. the area of △rst is equal to the area of △lmn. the area of △rst is 2 square units greater than the area of △lmn. the area of △rst is 4 square units greater than the area of △lmn.

Inscribe triangle RST in the square with dimensions 4×4, as shown in the figure. 

from the area of this square, 4*4=16, we remove the triangles with dimensions 
3×4, 2×1 and 2×4, whose side lengths are shown in the figure, and we are left with the area of triangle RST.

so  units squared

similarly, 

units squared

Thus, the areas are equal.