. The Decorator's assistant. Obs.—An angle which is either acute or obtuse is calledan oblique angle. The measure of any rectilinear angle isan arc of a circle contained between the two lines whichform that angle, the angular point or vertex being thecentre ; thus the arc a b is the measure of the rectilinearangle a b c. An angle is estimated by the number ofdegrees contained in the arc; whence a right angle is anangle of 90 degrees, or one-fourth of the circumference of acircle. Likewise, it makes no difference whether the areA B be a part of a larger or smaller circle described roundthe cent
. The Decorator's assistant. Obs.—An angle which is either acute or obtuse is calledan oblique angle. The measure of any rectilinear angle isan arc of a circle contained between the two lines whichform that angle, the angular point or vertex being thecentre ; thus the arc a b is the measure of the rectilinearangle a b c. An angle is estimated by the number ofdegrees contained in the arc; whence a right angle is anangle of 90 degrees, or one-fourth of the circumference of acircle. Likewise, it makes no difference whether the areA B be a part of a larger or smaller circle described roundthe centre b ; for the arc a b has the &?iV!xt proportion to thewhole circumference, as any other arc m n has to the wholeof that circumference of which it is a part; that is, there areas many degrees, minutes, &c., in a b as in m n. The com-plement of an angle is what it wants of 90 degrees; and thesupplement of an angle is what it wants of 180 25. is that which is enclosed by oneor more boundaries. 21. A circle is a plane figure bounded byone line, which is a curve, a b c d a, and whichis called the circumference; it is everywhere equally distant from a given point o, calledthe centre.
Size: 1841px × 1357px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury180, booksubjectart, booksubjectdecorationandornament
