The Total solution for NCERT class 6-12
Surfacearea of a cuboid = 1300 cm2Breadth (b) = 10 cmand height (h) = 20 cmLet l be the length, then= 2 (lb + bh + hl) = 1300lb+ bh + hl = 1300/2 =650l x 10 + 10 x 20 + 20 x l = 65010l + 20l + 200 = 650⇒ 30l =650 – 200 = 450⇒ l= 450/30 =15∴ Lengthof cuboid = 15 cm