## Chapter 9, Lesson 12

**9-12.A** understand the meaning of regular with respect to polygons** Which statement is not always true?I** If a triangle has three congruent sides, it also has three congruent angles. So an equilateral triangle is a regular polygon.

**II**If a quadrilateral has four congruent sides, it also has four congruent angles. So an equilateral quadrilateral is a regular polygon.

**III**If a pentagon has five congruent sides, it also has five congruent angles. So an equilateral pentagon is a regular polygon.

**(a)**I and II only

**(b)**I and III only

**(c)**II and III only

**(d)**III only

**9-12.B** find the sum of the measures of the interior angles of any polygon** What is the sum of the measures of the interior angles of any 12-gon?**

**9-12.C** find the measure of an interior angle of a regular polygon** What is the measure, to the nearest degree, of an interior angle of any regular 14-gon?**