1. An open tin box 21 cm long, 9 cm wide, 8cm high is fitted with a tin lid which overlaps to a depth of 1 cm all round.What is the total area of itn sheeting used for the box and the lid?

Asked by lakhwindersaggu2 | 19th Feb, 2017, 11:51: AM

Expert Answer:

begin mathsize 16px style Length space of space the space box comma space straight l equals 21 space cm
Breadth space of space the space box comma space straight b equals 9 space cm
Height space of space the space box comma space straight h equals 8 space cm
Area space of space the space sheet space required space for space making space the space box
equals 2 left parenthesis lh plus bh right parenthesis plus lb
equals 2 left parenthesis 21 cross times 8 plus 9 cross times 8 right parenthesis plus 21 cross times 9
equals 2 left parenthesis 168 plus 72 right parenthesis plus 189
equals 2 cross times 240 plus 189
equals 480 plus 189
equals 669 space cm squared
Length space of space the space lid equals 21 space cm
Breadth space of space the space lid equals 9 space cm
height space of space the space lid equals 1 space cm
Area space of space the space sheet space required space for space making space lid
equals 2 left parenthesis 21 cross times 1 plus 9 cross times 1 right parenthesis plus 21 cross times 9
equals 2 left parenthesis 21 plus 9 right parenthesis plus 189
equals 2 cross times 30 plus 189
equals 60 plus 189
equals 249 space cm squared
Total space sheet space required space to space make space the space box space and space lid equals 669 plus 249 equals 918 space cm squared end style

Answered by Rashmi Khot | 20th Feb, 2017, 11:05: AM