Question

if a:b=c:d then prove that ac÷bd=a square ÷ b square

Answer 1

a:b=c:d squaring on both sides gives
a²:b²=c²:d²_____(1)
c²:d²=c.c:d.d now replace one c:d by a:d (given a:b=c:d)
(1)==>a²:b²=ac:bd