(2^2+4^2+6^2+.....+20^2)=?	Options:
A) 770
B) 1155
C) 1540
D) 385x385
E) None of them
=(1x2)^2+(2x2)^2,+(2x3)^3+......(2x10)^2   =2^2 x (1^2+2^2+3^2+.......+10^2)   formula is =1/6 n(n+1)(2n+1)   =(4x1/6x10x11x21)   =(4x5x77)=1540   Answer is 1540
<result>C</result>
(2^2+4^2+6^2+.....+20^2)=?