This Basic geometry and measurement course is a refresher of length, area, perimeter, volume, angle measure, and transformations of 2D and 3D figures. If you are learning the content for the first time, …

This Basic geometry and measurement course is a refresher of length, area, perimeter, volume, angle measure, and transformations of 2D and 3D figures. If you are learning the content for the first time, …

Learn pre-algebra—all of the basic arithmetic and geometry skills needed for algebra.

Classify shapes and solve problems using what we know of the properties of shapes.

Geometry (all content) Unit 1: Lines Lines, line segments, and rays Measuring segments Parallel and perpendicular Points, lines, & planes Geometric definitions The golden ratio

Learn high school geometry—transformations, congruence, similarity, trigonometry, analytic geometry, and more (aligned with Common Core standards).

Khan Academy's Algebra 1 course is built to deliver a comprehensive, illuminating, engaging, and Common Core aligned experience! **Teaching this course? Check out our [teacher resources] …

Area and perimeter help us measure the size of 2D shapes. We’ll start with the area and perimeter of rectangles. From there, we’ll tackle trickier shapes, such as triangles and circles.

Learn early elementary math—counting, shapes, basic addition and subtraction, and more.

Learn to measure angles and understand their properties with Khan Academy's Unit 3 on basic geometry.