The naval architect's and shipbuilder's pocket-book of formulae, rules, and tables and marine engineer's and surveyor's handy book of reference (1884)
Mackrow, Clement · London, C. Lockwood and co. · leaf 36
R = ir 2 sm _n 2tan^ 6. To find the area of a regular polygon in terms of its sides,(Fig. 63.) Let EA, AB, bf be three conse-cutive sides of a regular polygon of en sides, and let each side = a. Bisect the angles EAB and ABFby the lines OA, ob, meeting in o.Draw OR at right angles to ab. Then area… … 28 MEASUREMENT OF AREAS BY TRIGONOMETRY. Fig. 64. 7. To find the area of a regular i)olygon. inscribed in a circle. (Fig. 64.) Let o be the centre of the circle, r the radiusuand AB a side of the polygon. Then area of polygon = -^-.sin lL. 2 n 8. To find the area of a regular polygon de-scribed…
