Lessons
Choose a lesson. Each lesson page has an overview of the main ideas, the lesson notes, the lesson video, any interactive activity for the lesson, and practice problems with feedback.
Foundations
Points, lines, planes, segments, and angles — the building blocks of geometry.
Vocabulary flash cards: Basics of Geometry — Flash Cards (PDF) · Print 2-sided, flipped on the long edge.
- Points, Lines, and Planes + Interactive ActivityOpen ›
- Measuring Segments + Interactive ActivityOpen ›
- Pythagorean Theorem + Interactive ActivityOpen ›
- Segment Addition + Interactive ActivityOpen ›
- Midpoint Formula + Interactive ActivityOpen ›
- Segment Bisector + Interactive ActivityOpen ›
- Partitioning a Directed Line Segment + Interactive ActivityOpen ›
- Angle Measurement + Interactive ActivityOpen ›
- Angle Relationships + Interactive ActivityOpen ›
Reasoning and Proof
Conditional statements, reasoning, and your first proofs.
Vocabulary flash cards: Reasoning and Proofs — Flash Cards (PDF) · Print 2-sided, flipped on the long edge.
Parallel Lines and Slope
Angle pairs formed by a transversal, proving lines parallel, and slope.
Vocabulary flash cards: Parallel and Perpendicular Lines — Flash Cards (PDF) · Print 2-sided, flipped on the long edge.
Triangles and Congruence
Classifying triangles and proving triangles congruent.
Vocabulary flash cards: Congruent Triangles — Flash Cards (PDF) · Print 2-sided, flipped on the long edge.
Transformations
Translations, reflections, rotations, and dilations.
Vocabulary flash cards: Transformations — Flash Cards (PDF) · Print 2-sided, flipped on the long edge.
Right Triangles and Trigonometry
The Pythagorean Theorem, special right triangles, and trigonometry in right triangles.
Vocabulary flash cards: Right Triangles and Trigonometry — Flash Cards (PDF) · Print 2-sided, flipped on the long edge.
Triangle Relationships
Special segments and inequalities within triangles.
Vocabulary flash cards: Special Segments and Inequalities Within Triangles — Flash Cards (PDF) · Print 2-sided, flipped on the long edge.
Similarity
Similar polygons and triangles, and proportional parts.
Quadrilaterals and Polygons
Parallelograms, rectangles, rhombuses, squares, trapezoids, kites, and polygons.
Vocabulary flash cards: Quadrilaterals and Other Polygons — Flash Cards (PDF) · Print 2-sided, flipped on the long edge.
Circles
Arcs, chords, angles, circumference, and equations of circles.
Vocabulary flash cards: Circles — Flash Cards (PDF) · Print 2-sided, flipped on the long edge.
Area and Probability
Area and perimeter of figures, probability, and geometric probability.
Vocabulary flash cards: Circumference, Area, and Volume — Flash Cards (PDF) · Print 2-sided, flipped on the long edge.
Volume and Surface Area
Volume and surface area of solid figures.
Vocabulary flash cards: Circumference, Area, and Volume — Flash Cards (PDF) · Print 2-sided, flipped on the long edge.