List of Formulas for Various Areas

Formulas for Various Areas

Plane Figures	Area1
triangle	ab/2
parallelogram	ab
rectangle	ab
square	s2
circle	πr2
Solids	Total Surface Area1
right circular cylinder	2πr(r + a)
right circular cone	πr(r + l)
sphere	4πr2

¹ The abbreviations used are: b = base (length of any side of a plane figure); a = altitude (perpendicular distance from the farthest point of the figure to the extended base); s = side; r = radius (of the base circle in the case of the cylinder or cone); l = slant height (distance from vertex to base of a cone measured on its surface).