| Area of a circle | D2 x 0.7854 = π r2 (r = radius) |
| Circumference of a circle | π D or 2π r |
| Area of a sphere | π D2 - 4π r2 (D + diameter) |
| Area of a triangle | 1/2 altitude x base |
| Volume of a cone | area of base x 1/3 alititude |
| Area of a trapezoid | 1/2 (sum of parallel sides) x altitude |
