...triangle through the axis and the fecond plane. Let there be a cane, its vertex the point Fig. A, and bafe the circle BC ; let it be cut by a plane through the axis, and let the triangle ABC be the fection ; let it be cut alfo by another plane, cutting its bafe in the direction...

...the triangle through the axis, and of the same plane cutting the base. Fig. is. Let there be a cone, the vertex of which is the point A, and the base the circle BC ; let it be cut through the axis by a plane, and let the section be the triangle ABC ; let it be also cut by another...

...any given straight line. Let there be a cone whose vertex is the point A and base the circle BF, and let it be cut by a plane through the axis, and let the section so made be the [axial] triangle ABF; now let it be cut by another plane cutting the circle BF in the...

...any given straight line. Let diere be a cone whose vertex is die point A and base die circle BF, and let it be cut by a plane through the axis, and let die section so made be die [axial] triangle ABF; now let it be cut by anodier plane cutting die circle...