Geometry Formulas – Circles, Sectors, Prisms, Cylinders & Cones

11 fill-in-the-blank flashcards covering essential geometry formulas for circles, sectors, prisms, cylinders, and cones.

The circumference of a circle is __.

2πr (two times pi times the radius)

The area of a sector is __.

(θ/360) × πr² (theta over 360 times pi times radius squared)

The arc length of a sector is __.

(θ/360) × 2πr (theta over 360 times two pi times radius)

The perimeter of a sector is __.

(θ/360) × 2πr + 2r (arc length plus two radii)

The volume of a prism is __.

Area of cross-section × length (or height)

The volume of a cylinder is __.

πr²h (pi times radius squared times height)

The surface area of a cylinder is __.

2πr² + 2πrh (two pi r squared plus two pi r h)

The volume of a cone is __.

(1/3)πr²h (one-third pi r squared times height)

The surface area of a cone is __.

πr² + πrl (base area plus curved area; l = slant length)

To find the cross-section of a prism you must first know __.

the shape of the cross-section (e.g., triangle, trapezium, etc.)

The area of a semicircle is __.

(1/2)πr² (one-half pi r squared)