1. Parallelogram (squares rectangular or rhomboidal) = the product of the length of one side X by perpendicular height. 2. Triangle = product of base X by onehalf the perpendicular height. 3. TriangleArea from 3 sides given. From the half sum of the three sides subtract each side separately; multiply the half sum and the three remainders together, and the square root of the product will be the area. 4. Trapezoid = the sum of the two parallel sides X by half the perpendicular height. 5. Circle = the square of the diameter X 0.7854, or square of the circumference X 0.07958. 6. Sector of a Circle = radius of the circle X by onehalf the arc of the sector. 7. Segment of a Circle.Find the area of a sector of a circle having the same arc, and deduct the triangle formed between the two radii and the chord of the arc. AREA OF SOLIDS: 8. Cube. 9. Parallelopipidon.} = { Sum of area of sides and bases. 10. Prism. 11. Cylinder = circumference of base X height + area of bases. 12. Cone. } = {Circumference of bases X onehalf slant height + area of 13. Pyramid. base. Sphere = square of diameter X 3.1416. French square metre, 1550.85 square inches = 10.7698 square feet. 
