CPCTC

CPCTC

An equilateral triangle is equiangular

KD = 2/3 JD

Definition

Definition

JK = 1/2 CK

The midsegment theorem

∠EAB = ∠FBA; ∠BAD = ∠ABD

EF ǁ AB; EF = 1/2 AB

Algebra

JK = 1/2 KD

Algebra

△AGD ≅ △BHD

AG + BH = 2/3 AB

Algebra

Algebra

The diagonals of a parallelogram bisect each other

AG = GH = HB = 1/3 AB

Triangles ABC, ABD equilateral; E and F midpoints of AC, BC

Side-Splitter theorem

Side-Splitter theorem

∠EDA = ∠FDB

∠EAD = ∠FBD

Algebra

ASA (Angle-Side-Angle)

AC = BC = BD = AD = AB

Definition

Substitution

SAS (Side-Angle-Side)

∠EAD = ∠EAB + ∠BAD; ∠FBD = ∠FBA + ∠ABD

GH = 2/3 EF

All rhombuses are parallelograms

ABCD is a rhombus

Points G and H trisect AB

Angle addition theorem

Given

ABCD is a parallelogram

AK = KB; CK = KD

GH = 1/3 AB

△EAD ≅ △FBD

AG = BH