i).find the surface area of a rectangular glass block whose volume is
1524cm^3 , if it is 72cm long and 48cm wide
That glass "block" which is is 72cm long and 48cm wide, is
less than half a centimeter high!
So it's not really a glass block. It's a sheet of glass to
be installed in a window as a window-pane!
So we wouldn't call the 0.4410 cm "the height", but rather,
"the THICKNESS" of the window pane.
The surface area is the total area of the front and back
surfaces which is two times this area:
A = LW
A = (72 cm)(48 cm)
A = 3456 cm2
Twice that is
Total area of front and back = 6912 cm2
The area of the left and right edges is twice this area:
A = LW (The width is the thickness)
A = (72 cm)(0.4410 cm)
A = 31.752 cm2
Twice that is 63.504 cm2
The area of the top and bottom edges is twice this area:
A = LW (The width is the thickness)
A = (48 cm)(0.4410 cm)
A = 21.168 cm2
Twice that is 42.336 cm2
Add all of it up:
Total area of front and back = 6912 cm2
Total area of left and right long edges = 63.504 cm2
Total area of top and bottom short edges = 42.336 cm2
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Total surface area = 7017.84 cm2
Edwin
