Volume of Cones, Cylinders, and Spheres Flashcards

Grade 8 · Math · Flashcards

Key formulas and concepts for 3D volume calculations.

Flashcards

Volume of a cylinder: V = pi x r^2 x h
Volume of a cone: V = (1/3) x pi x r^2 x h
Volume of a sphere: V = (4/3) x pi x r^3
Pi (approx.): 3.14159 — the ratio of circumference to diameter.
Radius from diameter: r = d/2; always halve the diameter before using formulas.
Cone-cylinder relationship: Cone is exactly 1/3 the volume of cylinder with same r and h.
Doubling the sphere's radius: Volume increases 8 times (r is cubed in the formula).
Cubic units: Volume units are cubed: cm^3, m^3, ft^3, in^3.
Height of a cone: Perpendicular distance from base to apex — not the slant height.
Hemisphere: Half a sphere; V = (2/3) x pi x r^3.
Finding r from diameter: If diameter = 10 then r = 5. Always divide by 2 first.
Archimedes' discovery: Sphere inside its circumscribed cylinder has V = (2/3) of the cylinder.