figure; and the measure of the base (of either of the derived figures of reference) happens to be the measure of the perpendicular (dropped to the base from either of the old-points of the topside in the required figure).
An example in Illustration thereof.
100. In relation to a quadrilateral with two equal sides constructed with the aid of 5 and 6 as bījas give out the measures of the top side, of the base, of (either of the two equal) sides, of the perpendicular (from the top to the base), of the diagonal, of the (lesser) segment (of the base), and of the area.
The rule for arriving at the measures of the top-side, of the base, of (any one of ) the (equal) sides, of the perpendicular (from the top to the base), of the diagonal, of the (lesser) segment (of the base) and of the area, in relation to a quadrilateral having three equal sides (with the aid of given bījas) :
The process will be clear from a comparison of the diagrams:
Area of the required quadrilateral, HA'FC' = area of the second rectangle EFGH.
Base A'F = perpendicular-side of the first rectangle plus perpendicular-side of the second rectangle. i.e., AB + EF.
Top side HC = perpendicular-side of the second rectangle minus perpendicular-side of the first rectangle i.e., GH - CD
Diagonal HF = diagonal of the second rectangle.
Smaller segment of the base, i.e., A'E= perpendicular-side of the first rectangle, i.e.,AB.
Perpendicular HE = base of the first or of the second rectangle, i.e.,BC or FG.
Each of the lateral equal sides A'H and FC' = diagonal of the first rectangle i.e., AC.
