Warm Up 1.) What does CPCTC stand for? 2.) What does CPCTC mean in your own words? 3.) a.) Why are the two triangles below congruent? b.) Using CPCTC name all the other corresponding parts that are congruent. R Z P Q X Y

Section 4.8: Isosceles and Equilateral Triangles Geometry Section 4.8: Isosceles and Equilateral Triangles Objective: SWBAT use theorems about isosceles and equilateral triangles.

Isosceles Triangle Isosceles Triangles have two congruent sides and two congruent base angles across from the congruent sides. A B and C are the base angles that are congruent because they are across from the congruent sides AC and AB. B C

Equilateral Triangle Equilateral Triangles have all three sides congruent to each other, so all three angles will also be congruent to each other. This makes all equilateral triangles also equiangular. A Angles A, B, and C are congruent because they are across from the congruent sides AC, CB, and AB. B C

Solve for the variable(s) and the ? 1.) 2.) 3.)

Solve for the variable(s). 4.) 5.) 6.)

Solve for the variable(s). 7.) 8.)

Class work: w/s 4.8 A: skip #’s 5, 6, 8, 9, 11, 13, 14, 16 Answers: 1.) EAC, ECA 2.) DA, DE 3.) BF, DF, BD 4.) ABC, BAC, BCA 7.) 18 10.) 3 12.) 8 15.) x = 15, y = 8 20.) 60 ft. 21.) 50 in. 22.) 69 m. 23.) 22 yd., x=42, y=69 24.) 1. given 17.) 25 ft. 18.) 28 in. 19.) 33 m.

Homework Page 267 – 277 #11-13 #15-17 #19-25 odds