Geometry Formulas Basics: Plane & Solid Figures
Geometry homework usually asks for one number—area, perimeter, volume, or surface area—from a labeled diagram. This guide groups the standard formulas so you pick the right tool.
Plane figures
Rectangles, triangles, circles, trapezoids, and ellipses each have a dedicated area formula. Perimeter sums boundary lengths; circles use circumference 2πr.
Solid figures
Boxes, cylinders, spheres, cones, and pyramids extend the same idea to volume and surface area. Keep units consistent—square vs cubic.