Question

derive the formula to calculate total surface area of cuboid. plzz fast its very urgent

Answer 1

let l, b and h be the length, breadth and height of a cuboid.

In a cuboid we have six faces,
front face area = h × b
back face area = h × b
top face area = l × b
bottom face area = l × b
left face area = h × l
right face area = h × l
Now total surface area of a cuboid is the total sum of the area of all the six faces.
T.S.A of cuboid = front face area + back face area + top face area + bottom face area + left face area + right face area
= hb + hb + bl + bl + lh + lh
= 2hl + 2bh + 2lb
= 2 (lb + bh + hl)
hence proved

Answer 2

Step-by-step explanation:

consider a cuboid whose length is 'L' cm, breadth b cm and height is h cm as shown in the above fig.

so,

Area of face ABCD =Area of face EFGH= (L×B) cm^2

Area of face AFHF=Area of face BFGC=(B×H) cm^2

Area of face ABEF =Area of face DHGC=(L×H) cm^2

Total surface area of the cuboid = sum of the areas of all its six faces

= 2(L×B) + 2( B×H) + 2(L×H) cm^2

=2(L×B + B×H + L×H) cm^2

=2( LB + BH + LH) cm^2

HOPE THIS WILL HELP U

PLEASE MARK ME AS BRAINLIST...