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Isosceles, Equilateral, and Right Triangles. Chapter 4.6. . Isosceles Triangle Theorem. Isosceles The 2 Base s are Base angles are the angles opposite the equal sides. B. A. C. If AB BC, then A C. Isosceles Triangle Theorem. B. A. C. If A C then AB BC.
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Isosceles, Equilateral, and Right Triangles Chapter 4.6
Isosceles Triangle Theorem Isosceles The 2 Base s are • Base angles are the angles opposite the equal sides.
B A C If AB BC, then A C Isosceles Triangle Theorem
B A C If A C then AB BC Isosceles Triangle Theorem
B A C Sample Problem Solve for the variables • mA = 32° • mB = (4y)° • mC = (6x +2)° 32 + 32 + 4y = 180 4y + 64 = 180 4y = 116 y = 29 6x + 2 = 32 6x = 30 x = 5
Find the Measure of a Missing Angle 120o 30o 30o 75o 30o 75o 180o – 120o = 60o 180o – 30o = 150o Lesson 6 Ex2
A • B • C • D A. 25 B. 35 C. 50 D. 130 Lesson 6 CYP2
A. B. C. D. A. Which statement correctly names two congruent angles? • A • B • C • D Lesson 6 CYP3
A. B. C. D. B. Which statement correctly names two congruent segments? • A • B • C • D Lesson 6 CYP3
Equilateral Triangle Theorem Equilateral Equiangular Each angle = 60o !!!
Use Properties of Equilateral Triangles Linear pair Thm. Substitution Subtraction Answer: 105 Lesson 6 Ex4
A • B • C • D A.x = 15 B.x = 30 C.x = 60 D.x = 90 Lesson 6 CYP4
A • B • C • D A. 30 B. 60 C. 90 D. 120 Lesson 6 CYP4
Don’t be an ASS!!! • Angle Side Side does not work!!! • (Neither does ASS backward!) • It can not distinguish between the two different triangles shown below. However, if the angle is a right angle, then they are no longer called sides. They are called…
Hypotenuse-Leg Theorem • If the hypotenuse and one leg of a right triangle are congruent to the corresponding parts in another right triangle, then the triangles are congruent.
Y B X Z A C ABC XYZ Why?HL Theorem
Z X Y M Prove XMZ YMZ Step Reason Given Given mZMX = mZMY = 90o Def of lines Reflexive ZMX ZMY HL Thm
AB XY • BC YZ • CA ZX Corresponding Parts of Congruent Triangles are Congruent • Given ΔABC ΔXYZ • You can state that: • A X • B Y • C Z
Suppose you know that ABD CDB by SAS Thm. Which additional pairs of sides and angles can be found congruent using Corr. Parts of s are ?
Complete the following two-column proof. Proof: Statements Reasons 1. Given 1. 2. 2. Isosceles Δ Theorem 3. 3. Given 4. 4. Def. of midpoint Lesson 6 CYP1
Statements Reasons 4. 4. Def. of midpoint ? 5. ______ 6. 6. ? 5. ΔABCΔADC Complete the following two-column proof. • A • B • C • D Proof: SAS Thm. Corr. Parts of s are Lesson 6 CYP1
Homework Video C Ch 4-6 • pg 248 1 – 10, 14 – 27, 32, 33, 37 – 39, & 48 Reminder! Midpoint Formula: