The sum of the length, breadth and height of a cuboidal box is 19 cm and the length of its diagonal is 11 cm. Find the surface area of the cuboidal box.

Asked by gpnkumar0 | 5th Aug, 2016, 06:06: PM

Expert Answer:

begin mathsize 16px style Let space the space length comma space breadth space and space height space of space the space cuboid space be space straight l comma space straight b space and space straight h space respectively.
Given space that space straight l space plus space straight b space plus thin space straight h space equals space 19 space cm
Length space of space diagonal space of space the space cuboid equals square root of straight l squared plus straight b squared plus straight h squared end root equals 11 space cm
rightwards double arrow straight l squared plus straight b squared plus straight h squared equals 121
We space know space that comma
left parenthesis straight l plus straight b plus straight h right parenthesis squared equals straight l squared plus straight b squared plus straight h squared plus 2 lb plus 2 bh plus 2 hl
rightwards double arrow left parenthesis 19 right parenthesis squared equals 121 plus 2 lb plus 2 bh plus 2 hl
rightwards double arrow 361 equals 121 plus 2 lb plus 2 bh plus 2 hl
rightwards double arrow 2 lb plus 2 bh plus 2 hl equals 240
rightwards double arrow The space surface space area space of space straight a space cuboid equals 240 space cm squared... left parenthesis Since space surface space area space of space straight a space cuboid equals 2 lb plus 2 bh plus 2 hl right parenthesis
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Answered by Rebecca Fernandes | 7th Aug, 2016, 09:58: AM