Discovering the Basics of Geometry

Geometry is all about shapes, sizes, and how objects are positioned in space. In 8th grade, you'll work with points, lines, angles, and two- and three-dimensional shapes.

Key Concepts

• Points: Exact locations (no size).
• Lines: Straight, endless in both directions.
• Angles: Made by two rays meeting at a point.
• Polygons: Closed shapes with straight sides (like triangles and rectangles).

Measuring and Calculating

You’ll use formulas to find perimeter, area, and volume:

• Perimeter of a rectangle: \( P = 2l + 2w \)
• Area of a triangle: \( A = \frac{1}{2}bh \)
• Volume of a rectangular prism: \( V = lwh \)

Why Geometry Is Useful

Geometry helps you design spaces, build objects, and understand the world—like measuring a room or figuring out how much paint you need for a wall.

Geometry Tips

• Draw a sketch to help visualize problems.
• Label all known lengths and angles.