Alternative method: If you didn’t see the similar triangles, or if you didn’t
know for sure how the area of the larger triangle is related to the area of the
smaller triangle, you at least could have eliminated some answer choices
based on appearances. Look at the figure and use your eyes to compare the
areas. (We call this method eyeballing.) Doesn’t it look as though the larger
triangle has more than twice as much room inside it as the smaller triangle?
That means that answer choices (A), (B), and (C) are all visibly too small. If you
can narrow the choices down to two, it certainly pays to guess.
Eyeballing is never what you’re supposed to do to answer a question, but if
you don’t see a better way, eyeballing’s better than skipping.
EYEBALL THE FIGURE
You can assume that a figure is drawn to scale unless the problem says
otherwise. So when you’re stuck on a geometry question and don’t
know what else to do, see if you can at least use your eyes to eliminate
a few answer choices as visibly too small or too big.THREE SPECIAL TRIANGLE TYPES
Three special triangle types deserve extra attention:
Isosceles triangles
Equilateral triangles
Right triangles