A new manual of the elements of astronomy, descriptive and mathematical .. (1868)
Kiddle, Henry, 1824-1891 · New York, Ivison, Phinney, Blakeman & co.; Chicago, S.C. Griggs & co. · leaf 18
Questions.—a. How dependent on the distance of an object? Explain from the dia-gram. 20. How is an angle measured ? 21. What is aright angle? 22. When is oneline perpendicular to another? 23. When is a straight line perpendicular to a circle ?24 What is an acute angle ? An obtuse angle ? Illustrate… … ^B In the annexed diagram, the semi-cir-cumference is used to measure all theangles having their vertices, or angularpoints, at C. Thus BCD, containingthe arc B D, is an angle of 45°; B C E,an angle of 90°; and BCF, of 120°.The points A and B are at the angulardistance of 180°, or two right…
Astronomy
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