This page focuses on the fundamental calculations for two-dimensional geometric shapes, including perimeter and area formulas for basic planar figures.

Definition: A two-dimensional shape is a flat figure that has only length and width.

Vocabulary:

• Disc (Disque): A flat, circular shape
• Triangle: A polygon with three sides
• Rectangle: A quadrilateral with four right angles
• Parallelogram: A quadrilateral with opposite sides parallel

Example: For a triangle:

• Area = (base × height) ÷ 2
• Where base and height must be perpendicular to each other

Highlight: The perimeter formulas focus on the sum of all sides, while area formulas typically involve multiplication of key dimensions.

This page covers the fundamental volume and surface area calculations for three-dimensional geometric shapes. The formulas presented are essential for spatial geometry calculations.

Definition: A three-dimensional shape is a solid figure that has length, width, and height.

Vocabulary:

• Sphere (Sphère): A perfectly round three-dimensional object
• Cube: A solid object with six equal square faces
• Pyramid: A polyhedron with a polygonal base and triangular faces
• Cylinder: A three-dimensional solid consisting of two parallel circular bases

Example: For a sphere with radius R:

• Surface Area = 4πR²
• Volume = $4/3$πR³

Highlight: The cylinder's volume formula (πR²h) can be understood as the area of its circular base (πR²) multiplied by its height $h$.