Question

Find the cost of polishing a cuboid at Rs.2.50 per sq.m whose length,breadth and height are 4m,3.5m,and 3m respectively​

Answer 1

$TSA \: \: of \: \: Cuboid = 2( lb+bh + lh) \\ \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 2[(4 \times 3.5) + (3.5 \times 3) + (4 \times 3)] \\ \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 2[(14) + (10.5) + (12)] \\ \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = (28 + 21 + 24) {m}^{2} \\ \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 73 {m}^{2}$

Hence,

Cost of polishing=73×2.5
= ₹ 182.5

Answer 2

Answer

We are given the length, height, and breadth

length - 4 m

breadth - 3.5 m

height - 3 m

We have to find the cost of polishing the cuboid at 2.50 Rs.

We can use the TSA cuboid formula-

$2(lb + bh + hl)$

here, l = length

b= breadth

h= height

putting the values in the respective formula

$2(lb + bh + hl)$

$2(4\times 3.5 + 3.5\times 3 + 3\times 4)$

$2(14 + 10.5 + 12)$

$2(36.5)$

$2\times 36.5$

$=73$

Now, finding the cost of painting at 2.50 Rs.

$73\times cost$

$73\times 2.50$

$182.5 Rs$