Browse lessons by topic. Click a topic title to open the full topic page, or click a lesson title to start learning.
Coordinate Geometry
Learn about dimensions, points, and distances in \(1D, 2D,\) and \(3D\).
Introduction
- Length, Area, and Volume: What’s the Difference?
- Difference between \(1D, 2D,\) and \(3D\)
- \(3D, 4D,\) and Beyond in Real Life
\(1D\) (Number Line)
- Plotting Points on a Number Line (\(1D\))
- Distance Formula in \(1D\)
- Distance between Two Points in \(1D\)
B) \(2D\) (Coordinate Plane)
- Plotting Points on the Coordinate Plane (\(2D\))
- Which Quadrant or Axis? Points on the Coordinate Plane \(2D\)
- Distance Formula in \(2D\)
- Distance between Two Points in \(2D\)
Pythagorean Theorem
Learn how the Pythagorean Theorem works, why \(a^2+b^2=c^2\), and how to use it in examples.
- Pythagorean Formula
- Pythagoras Theorem (\(a^2 + b^2 = c^2\)) – Visual Proof 1
- Pythagoras Theorem (\(a^2 + b^2 = c^2\)) – Visual Proof 2
- Pythagoras Theorem (Example)
Triangles
Learn the basic properties of triangles, including triangle types, angle sums, missing angles, and exterior angles.
Introduction
Interior Angles
Exterior Angles
- Sum of Exterior Angles of a Triangle (Proof)
- Exterior Angle Theorem of a Triangle
- Two Exterior Angles at a Vertex are Equal (Proof)
- Two Exterior Angles are Equal at a Vertex (Quick Proof)
Polygons
Learn about polygon types, interior angles, exterior angles, and formulas for regular and irregular polygons.
Introduction
Interior angles
- Sum of Interior Angles of a Polygon (Proof)
- Find Missing Interior Angles of a Polygon (Examples)
- Why Regular and Irregular Polygons Have Different Angle Formulas?
Exterior angles
- Sum of Exterior Angles of Regular Polygons (Proof)
- Sum of Exterior Angles of Convex Polygons (Proof)
Circle
Learn about \(\pi\), radius, diameter, circumference, and area.
- What is \(\pi\) (pi)? An Easy Explanation
- Why the Area of a Circle is \(\pi r^2\) (Visual Explanation)
Algebra, Calculus, and Trigonometry
Learn key ideas from algebra, calculus, and trigonometry, including identities, derivatives, and common trigonometric values.
Algebra
- \((a – b)^2\) – Geometric Derivation
- \((a + b)^2\) – Geometric Derivation
- \(a^2 – b^2\) – Geometric Derivation
- \(a^2 – b^2\) – Algebraic Proof