Home / Courses / Geometry

Geometry

Free Geometry study guide: 9 units with summaries, key ideas, flashcards and 307 practice questions with step-by-step solutions.

Lines up with: SAT: Geometry and Trigonometry; state end-of-course exams.

Units

1. UNIT 01

   Points, lines, angles & coordinates

   Geometry starts with the vocabulary of points, lines and angles, plus two coordinate formulas you'll use all year.
2. UNIT 02

   Parallel lines & polygon angles

   When a transversal crosses parallel lines it creates predictable angle pairs. These lead to the angle-sum facts for triangles and polygons.
3. UNIT 03

   Congruent triangles & proof

   Congruent triangles have all matching sides and angles equal. You don't need all six facts: a few shortcuts prove congruence.
4. UNIT 04

   Similarity & right triangles

   Similar figures have the same shape but different size. Their sides are proportional, and right triangles have special relationships of their own.
5. UNIT 05

   Right-triangle trigonometry

   Trig ratios connect a right triangle's angles to its side lengths, so you can find missing sides or angles.
6. UNIT 06

   Area of polygons & circles

   Area measures the space inside a 2D shape in square units. Most formulas come from the rectangle.
7. UNIT 07

   Circles

   Circle theorems relate angles to the arcs they cut off. The coordinate equation of a circle comes from the distance formula.
8. UNIT 08

   Surface area & volume

   Volume measures space inside a 3D solid; surface area measures the outside. Most volume formulas are base area times height, sometimes with a ⅓.
9. UNIT 09

   Transformations

   Transformations move or resize figures. Rigid motions (translate, reflect, rotate) keep size and shape; dilations keep shape but change size.