Perimeter, area and units
Perimeter is the distance around a shape; area is the space inside it. Five area formulas cover almost every straight-sided shape, and compound shapes are just these pieces added or subtracted. When converting area units, square the length conversion.
≈ 30 minCircles, arcs and sectors
Circumference and area . A sector is a fraction of the circle, so its arc and area are that fraction of the circumference and area. Its perimeter is the arc plus two radii.
≈ 30 minPrisms and cylinders
A prism has the same cross-section all the way through, so its volume is cross-section area length. A cylinder is a prism with a circular cross-section. Surface area is the total area of every face: unfold the solid into a net and add.
≈ 30 minPyramids, cones and spheres
A pyramid or cone holds exactly one third of the prism with the same base and height. A sphere has volume and surface area . Composite solids are built from these pieces: add the volumes, and count only the outside surfaces.
≈ 35 min