A treatise on special or elementary geometry (1877)
Olney, Edward, 1827-1887, Olney, Edward, 1827-1887. Elements of trigonometry, plane and spherical · New York : Sheldon · leaf 79
58 ELEMENTARY GEOMETRY. 7. Construct a regular octagon.SuG.-See the general solution {121). … Fia. 101. 8. Construct a regular nonagon. Solution.—First get a quarter of the cir-cumference by marking the points where twodiameters at right angles to each other wouldcut the circumference. AX is an arc of 90°.Then from A take AY = 60° by using radius asa chord. YX is therefore an arc of 30°.…
Geometry · Trigonometry
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