# EQUAL

, a term of relation between different things, but of the same kind, magnitude, quantity, or quality.——Wolfius defines Equals to be those things that may be substituted for each other, without any alteration of their quantity.—It is an axiom in mathematics &c, that two things which are equal to the same third, are also equal to each other. And if Equals be equally altered, by Equal addition, subtraction, multiplication, division, &c, the results will be also Equal.

Equal *Circles,* are those whose diameters are
equal.

Equal *Angles,* are those whose sides are equally inclined,
or which are measured by similar arcs of circles.

Equal *Lines,* are lines of the same length.

Equal *Plane Figures,* are those whose areas are
equal; whether the figures be of the same form or
not.

Equal *Solids,* are such as are of the same space, capacity,
or solid content; whether they be of the
same kind or not.

Equal *Curvatures,* are such as have the same or
equal radii of curvature.

Equal *Ratios,* are those whose terms are in the same
proportion.

, in Optics, is said of things that are seen under equal angles.