Question

a poster measurung 20cm×16cm is pasted on a sheet of a cardboard such that there is a margin of 3.5cm along each sidefind the total area of the margin

Answer 1

area of poster=20*16=320 cm^2
length of cardboard=20+3.5=23.5 cm
breadth of cardboard=16+3.5=19.5 cm
area of cardboard=23.5*19.5=458.25 cm^2
area of margin= 458.25 - 320 = 138.25 cm^2


here  ( * )   =multiplication and (^2)=square

Answer 2

Length of cardboard - 20+(3.5+3.5) - 27cm
breadth of cardboard - 16+(3.5+3.5) - 23cm

Area of margin = Ar(Cardboard)-Ar(Poster)
= 27×23 - 20×16
= 621 - 320
= 301cm^2