Plane Figure Geometry Formulas: Name Rectangle Perimeter/Circumference Area (A) Parallelogram P 2a 2b A bh Trapezoid Add all four exterior lengths A 1 h( a b ) 2 Triangle Add all three exterior lengths A 1 bh 2 C 2 r A r2 d2 A 4 Circle Figure P 2L 2W **for a circle, perimeter is renamed circumference since it is the measure of a curve Sector L 180 r A LW this formula can be used if the diameter (d) is known instead of the radius A 360 **for a sector, perimeter is renamed arc length Ellipse C ( a b) j 1 1 2 1 3 j 1 h h h ... 4 64 256 ( a b) 2 h ( a b) 2 A ab r2 Solid Figure Geometry Formulas: Name Rectangular Prism Figure Surface Area (SA) Volume (V) Triangular Prism SA ab d (a b c) 1 V abd 2 Cylinder SA 2 r 2 2 rh V r 2h d 2h V 4 SA 2wl 2hl 2wh V lwh this formula can be used if the diameter (d) is known instead of the radius Pyramid SA b2 b b2 4h2 1 V b2h 3 Cone SA r 2 r r 2 h 2 1 V r 2h 3 Frustum of a Pyramid SA b 2 B 2 1 V h B 2 Bb b 2 3 Frustum of a Cone Sphere ( B b) ( B b ) 2 h 2 SA r 2 R 2 ( R r ) ( R r )2 h2 SA 4 r 2 1 V h R 2 Rr r 2 3 4 V r3 3