how can you find the surface area of a cube,cuboid,cone and a pyramid by using flat cut outs?
Answer :
Surface area of cube
So
Surface area of cube = sum of area of all six square
= a2 + a2 + a2 + a2 + a2 + a2
Surface aarea of cube = 6 a2 ( Ans )
Surface area of cuboid
Surface area of cuboid = Sum of area of all six rectangles
= lb + lb + bh + bh + lh + lh
So
Surface area of cuboid = 2 ( lb + bh + lh ) ( Ans )
Surface area of pyramid
Surface area of pyramid = Area of base square + sum of all four triangles
Let sides of square = a
So,
Base of triangles = a
And
Height of triangles = h
= a2 + 4 ( ah )
= a2 + 2 ah
So,
Surface area of pyramid = a2 + 2 ah
Surface area of Cone
Surface area of Cone = Area of base square + area of arc
here s = slant height of cone
r = radius of base
=
So,
Surface area of Cone = ( Ans )
Surface area of cube
So
Surface area of cube = sum of area of all six square
= a2 + a2 + a2 + a2 + a2 + a2
Surface aarea of cube = 6 a2 ( Ans )
Surface area of cuboid
Surface area of cuboid = Sum of area of all six rectangles
= lb + lb + bh + bh + lh + lh
So
Surface area of cuboid = 2 ( lb + bh + lh ) ( Ans )
Surface area of pyramid
Surface area of pyramid = Area of base square + sum of all four triangles
Let sides of square = a
So,
Base of triangles = a
And
Height of triangles = h
= a2 + 4 ( ah )
= a2 + 2 ah
So,
Surface area of pyramid = a2 + 2 ah
Surface area of Cone
Surface area of Cone = Area of base square + area of arc
here s = slant height of cone
r = radius of base
=
So,
Surface area of Cone = ( Ans )