...Draw the figure required for the construction of a regular pentagon inscribed in a given circle. 11. Triangles of the same altitude are to one another as their bases. ADD, BOB are diameters of the circle ABDE and are at right angles to each other ; the arcs AB, BD are...

...and 15, and the definition of reciprocal proportionals. EUCLID, VI. 1. Triangles and parallelograms of the same altitude are to one another as their bases. Let the triangles ^ XF ABC, ACD and the parallelograms EC, CF have the same altitude, namely, the perpendicular...