3 – 2 Ditto; HW Answers

2) – same-side 3) None4) - same-side5) - corresponding6) - corresponding7) – same-side

8) x = 439) x = 9010)x = 3811)x = 10012)x = 7013) x = 48

Section 3 – 3 Parallel Lines & The Triangle Angle-Sum TheoremObjectives:To classify triangles and find the measures of their angles

To use exterior angles of triangles

Triangle Angle-Sum Theorem:The sum of the measures of the angles of a

triangle is 180.

Example 1 Applying the Triangle Angle-Sum Theorem

A) Find m 1

B) Δ MNP is a right triangle. is a right angle and m is 58. Find m

MN P

Example 2 Using AlgebraA) Find the values of x, y, and z.

B) Find the values of a, b, and c.

C) Find the values of x, y, and z.

Classifying TrianglesBy Angles

Classifying TrianglesBy Sides

Example 3 Classifying a Triangle

A) Classify the triangle by its sides and its angles.

Draw and mark a triangle to fit each description. If no triangle can be drawn, write not possible.B) Acute Scalene

C) Isosceles Right

D) Obtuse Equiangular

Exterior Angle:An angle formed by a side and an extension of an adjacent side

Remote Interior Angles:For each exterior angle, the two nonadjacent interior angles of the triangle

Triangle Exterior Angle Theorem:The measure of each exterior angle of a triangle equals the sum of the measures of its two remote interior angles.

Example 4 Using the Exterior Angle Theorem

Find the measure of each missing angle.