Geometry - Overview

The Geometry domain covers plane geometry, coordinate geometry, trigonometry, circles, polygons, and three-dimensional figures.

Geometry remains an important part of ACT Math and rewards strong visualization skills.

TipWhat You’ll Learn

By working through this domain, you’ll learn how to:

  • Analyze geometric figures
  • Solve angle and triangle problems
  • Apply the Pythagorean Theorem
  • Work with circles and polygons
  • Use coordinate geometry
  • Apply trigonometric relationships
  • Calculate area, volume, and surface area

Course Structure

Topics in this domain include:

  • Lines and angles
  • Triangles
  • Similarity and congruence
  • Polygons
  • Circles
  • Coordinate geometry
  • Three-dimensional figures
  • Trigonometry
  • Radians and unit circle concepts

ACT Geometry Tips

  • Draw and label diagrams.
  • Memorize key geometry formulas.
  • Use special right triangles efficiently.
  • Check whether trigonometry simplifies the problem.
  • Watch units when calculating area and volume.

Assess Your Progress

After completing the lessons, reinforce your understanding through:

  • Lesson practice questions
  • Unit assessments
  • ACT Domain Tests
  • Full-Length ACT Practice Tests

Select a topic from the sidebar to begin.