Cylinders and Spheres (Leaving Cert Mathematics): Flashcards

$\pi r^2 h$

$2\pi rh$

$2\pi r(h + r)$

$\frac{4}{3}\pi r^3$

$4\pi r^2$

$\frac{2}{3}\pi r^3$

$3\pi r^2$

3D shape with two parallel circular bases and curved surface

Perfectly round 3D shape, all points equidistant from centre

Exactly half of a sphere

Curved half + flat base: $2\pi r^2 + \pi r^2 = 3\pi r^2$

Set volume formulas equal when shapes have same volume

Cancel $\pi$ from both sides to simplify calculation