Question

Raju wants to paint a cuboidal box which is 20 cm in length , 15 cm in breadth and 6 cm in depth. Find the area to be painted if the box is open at the top.​

Answer 1

Answer:

ɢɪᴠᴇɴ:-

Length (l) = 20 cm

Breadth (b) = 15 cm

Height (h) = 6 cm

ᴛᴏ ғɪɴᴅ :-

Area of Box open at the top

sᴏʟᴜᴛɪᴏɴ :-

We know that,

Area of Cuboid(Box) = 2(lb + lh + bh)

➮ 2(lb + lh + bh)

➮ 2(20 × 15 + 20 × 6 + 15 × 6)

➮ 2(300 + 120 + 90)

➮ 2(510)

➮ 1020 cm²

Now,

Required area of Box = Area of box - Area of Top

➮ Required area = 1020 - (l × b)

➮ 1020 - (20 × 15)

➮ 1020 - 300

➮ 720 cm²

Hence,

Area of Box to be painted is 720 cm²

TO MORE INFORMATION :-

Total Surface Area of a Cuboid (TSA) = 2 (lb + bh + lh) square units

Lateral Surface Area of a cuboid (LSA) = 2h (l+b) square units

Volume of the cuboid (v) =lbh

Answer 2

Length =20 cm

Breadth given =15 cm

Height =6 cm

So,area of cuboid =2×(lb+bh+lh)

=2×(20×15+15×6+6×20 ) cm

=2×(300+90+120) cm

=2×510 cm

=1020 cubic cm

Required area =area of box -area of top

=1020-(20×15) =1020-300=720 cubic cm

Hope it helps

Thanks