alanforde800Maximus
How many sides does polygon P have?
(1) All sides of P have equal lengths.
(2) The sum of the measures of the interior angles of P is \(1,440^{\circ}\)
Target question: How many sides does polygon P have? Statement 1: All sides of P have equal lengths. There are infinitely many polygons that satisfy statement 1. Here are two:
Case a: Polygon P is an equilateral triangle. In this case, the answer to the target question is
polygon P has 3 sidesCase b: Polygon P is a square. In this case, the answer to the target question is
polygon P has 4 sidesSince we cannot answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: The sum of the measures of the interior angles of P is 1440ºUseful rule:
the sum of the angles in an n-sided polygon = (n - 2)(180º)So, we can write the equation: (n - 2)(180º) = 1440º
STOP: We need not solve this equation for n.
We need only recognize that we COULD solve it for n (but we won't, because that would be a waste of valuable time)
Since we COULD answer the
target question with certainty, statement 2 is SUFFICIENT
Answer: B
Cheers,
Brent