Mathematics in Ancient and Medieval India c6.s9.51

c6.s9.51

$= ½ ab(R Sin B)/R + ½cd (R Sin D)/R [ From (1) ]$ $= ½ ab(R Sin B)/R + ½ cd(R Sin (180⁰-B))/R$ $= ½ ab(R Sin B)/R + ½ cd(R Sin B)/R$ $= ½(ab+cd)(R Sin B)/R$ $= √((s-a)(s-b)(s-c)(s-d)) [ From (5) ]$