# Geometry

**Basic Concepts of Geometry**

Lesson 1: Points, Lines, and Planes

Lesson 2: How to Name Angles

Lesson 3: How to Measure Angles

Lesson 4: Definition and Names of Polygons

Lesson 5: Parts of a Triangle

Lesson 6: Types of Triangles According to Sides and Angles

Lesson 7: Lines, Rays, and Segments

Lesson 8: Meaning of Collinear and Coplanar

Lesson 9: Congruence of Segments

Lesson 10: Congruence of Angles

Lesson 11: Complementary and Supplementary Angles

Lesson 12: Adjacent Angles and Linear Pairs

Lesson 13: Vertical Angles – Definition and Proof

Lesson 14: Parallel, Perpendicular, and Skew Lines

**Quadrilaterals**

Lesson 1: Basic Terminologies about Quadrilaterals

Lesson 2: Sum of the Interior Angles of Quadrilateral

Lesson 3: Definition of Parallelogram and Its Properties

Lesson 4: Proof that Opposite Sides of a Parallelogram are Congruent

Lesson 5: Proof that Opposite Angles of Parallelogram Are Congruent

Lesson 6: Proof that Diagonals of Parallelograms Divide it to Congruent Triangles

Lesson 7: Proof that Diagonals of a Parallelogram Bisect Each Other

Lesson 8: Proof that if Opposite Sides of a Quadrilateral are Congruent It is a Parallelogram

Lesson 9: Proof that if Opposite Angles of a Quadrilateral are Congruent It is a Parallelogram

Lesson 10: If the diagonals of a quadrilateral bisect each other, it is a parallelogram

Lesson 11: If one pair of sides of a quadrilateral are both congruent and parallel, it is a parallelogram

Lesson 12: Definitions of Rectangles, Rhombuses, and Squares

Lesson 13: Diagonals of a Rectangle are Congruent

Lesson 14: Diagonals of a Rhombus are Perpendicular

Lesson 15: Definition and Parts of a Trapezoid

Lesson 16: Base Angles of Isosceles Trapezoid are Congruent

**Triangle Congruence**

Lesson 1: Introduction to Triangle Congruence

Lesson 2: Minimum Conditions for Triangle Congruence

Lesson 3: The SSS Congruence

Lesson 4: The ASA Congruence

Lesson 5: The SAS Congruence

Lesson 6: Sample Proof Using SSS Congruence

Lesson 7: Sample Proof Using ASA Congruence

Lesson 8: Sample Proof Using SAS Congruence

Lesson 9: Leg Leg Congruence (LL Congruence)

Lesson 10: Leg Angle Congruence (LA Congruence)

Lesson 11: AAS Congruence and its Proof

Lesson 12: Hypotenuse Angle Congruence