This PPT features a well explained theory / concepts / derivations of the formula of Surface Area of various 3D shapes : like cube, cuboid and cylinder with the help of expanded 3D shapes (called "nets"). NOTE: # THIS IS PDF FILE SO IF YOU WANT TO DOWNLOAD THE PPT FILE THEN DOWNLOAD IT FROM THE DROPBOX LINK AS GIVEN: https://www.dropbox.com/s/mud0yx2tfoscx2y/Surface%20Area%20PPT.pptx # FOR BETTER EXPERIENCE VIEW THE PPT AFTER DOWNLOADING IN PPT SLIDESHOW........:-)

2. This shows that the outer surface of a cube is made up of
six squares but in fact they are the faces of cube. So,
Surface area of cube = Area of all six squares
Surface area of cube = a2 + a2 + a2 + a2 + a2 + a2
Surface area of cube = 6a2

3. This shows that the lateral or curved surface of a cube is
made up of four squares. So,
Lateral or curved surface area of cube = Area four squares
Lateral or curved surface area of cube = a2 + a2 + a2 + a2
Lateral or curved surface area of cube = 4a2

4. This shows that the outer surface of a cuboid is made up of
six rectangles but in fact they are the faces of cuboid. So,
Surface area of cuboid = Area of all six rectangles
Surface area of cuboid = (lb)+(lb)+(bh) +(bh) + (hl) +(hl)
Surface area of cuboid = 2(lb)+2(bh)+2(hl)
Surface area of cuboid = 2(lb+bh+hl)

5. This shows that the lateral or curved surface of a cuboid is
made up of four rectangles. So,
Lateral or curved surface area of cuboid = Area of four
rectangles
Lateral or curved surface area of cuboid
=(bh)+(bh)+(hl)+(hl)
Lateral or curved surface area of cuboid = 2(bh)+2(hl)
Surface area of cuboid = 2(l+b)h

6. This shows that the outer surface of a cylinder is made up
of one rectangle and two circles. So,
Surface area of cylinder = Area of rectangle + Area of two
Circles
Surface area of cylinder = 2 ‫ת‬rh + ( ‫ת‬r2 + ‫ת‬r2 )
Surface area of cylinder = 2 ‫ת‬rh + 2(‫ת‬r2)
Surface area of cuboid =2 ‫ת‬r(r+h)
‫ת‬
‫ת‬

7. This shows that the lateral or curved surface of a cylinder
is made up of one rectangle. So,
Lateral/curved surface area of cylinder = Area of rectangle
Lateral/curved surface area of cylinder = 2 ‫ת‬rh
‫ת‬
‫ת‬

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