4.1 NotesClassifying Triangles

Classification of Triangles by Angles

Example 1Classify the triangles below by the angles.

Example 2The frame of this window design is made up of many triangles.

Classify ΔACD

Classify ΔADE

Example 3Classify ΔXYZ as acute, equiangular, obtuse, or right. Explain your reasoning.

Lesson goals: I can classify triangles by their angle measures and side lengths I can solve problems using the classifications of triangles

Classification of Triangles by Sides

Example 4The triangle truss shown is modeled for steel construction. Classify ΔJMN, ΔJKO, and ΔOLN as equilateral, isosceles, or scalene.

Classify Triangles by Sides Within Figures

Example 5: If point Y is the midpoint of VX, and WY = 3.0 units, classify ΔVWY as equilateral, isosceles, or scalene. Explain your reasoning.

Example 6If point C is the midpoint of BD, classify ΔABC as equilateral, isosceles, or scalene.

Example 7Find the measures of the sides of isosceles triangle KLM with base KL.

Example 8Triangle FGH is an equilateral triangle. Find the value of y, then find the measurements of each side.

4.2 NotesAngles of Triangles

Angle Sum Theorem

Example 1The diagram shows the path of the softball in a drill developed by four players. Find the measure of each numbered angle.

Example 2The picture below shows the path of a passing soccer ball. Find the numbered angle measures.

Lesson goals: I can use the Triangle Angle-Sum Theorem to

solve for missing angles. I can use the Exterior Angles Theorem to solve for

missing angles

Example 3Find the measure of each numbered angle.

Exterior Angle Theorem

Example 4Find the measurement of angle JKL in the Triangle Pose shown.

Example 5Find the measure of ÐFLW.

Example 6Tonya places shelving brackets in her closet, shown below. Find the measurement of Ð1, the angle that the wall and bracket make.

HW PG 240 # 1-13 and PG 250 # 1-11 and 17-18 Please show work for full credit on this assignment