Let \\\\(ABCD\\\\) be a trapezium with parallel sides \\\\(AB\\\\) and \\\\(CD\\\\)Let \\\\(AB=20\\\\) ....... (Given) and \\\\(CD=x\\\\)\\\\(A(\\square ABCD)=480\\ m^2, \ ext{height}(h)=15\\ m\\\\) .......... (Given)We know that, \\\\(A(\\square ABCD)=\\dfrac{(AB+CD)}{2}\ imes h \\\\)\\\\(\\implies 480 =\\dfrac{20+x}{2}\ imes 15\\\\)\\\\(\\implies \\dfrac{2\ imes 480}{15}=20+x\\\\)\\\\(\\implies 64=20+x\\\\)\\\\(\\implies x=44\\\\)Hence, length of other parallel side \\\\(CD\\\\) is \\\\(44\\ m\\\\).