Try to put all the given information into the figure so that you can see
everything at a glance and don’t have to keep going back and forth
between the question stem and the figure.
Watch out! That matches choice (B), but it’s the answer to the wrong
question. What you’re looking for is PR, so you have to add:
PR = PQ + QR = (6x − 10) + (−2x + 11) = 4x + 1
The answer is (E).
BASIC TRAITS OF TRIANGLES
Most Math 1 plane geometry questions are about closed figures: polygons and
circles. And the test makers’ favorite closed figure by far is the three-sided
polygon; that is, the triangle. All three-sided polygons are interesting because
they share so many characteristics, and certain special three-sided polygons
—equilateral, isosceles, and right triangles—are interesting because of their
special characteristics.
Let’s look at the traits that all triangles share.
Sum of the interior angles: The three interior angles of any triangle add up to
180°.