Question

Length breadth and height of a cuboid are in the ratio 6:5:4 if its volume is 15000 find its surface​

Answer 1

Answer:

Step-by-step explanation:let

l=6x

b=5x

h=4x

as volume=l*b*h

so, 120x3=15000

     x3=125

x=5  

so, l=30

b=25

h=20

now sa=2(lb+bh+hl)

sa=2(750+500+600)

sa=2*1850

sa=3700 square units

Answer 2

Question

1. The length, breadth and height of a cuboid are in the ratio 6:5:4. If its volume is 15,000 cm^3, find :

(i) its dimensions                    (ii) its surface area

Solution

 Dimensions means : its length, breadth and height

(i) Given : Length : breadth : height = 6 : 5 : 4

 ⇒ If length = 6x cm, breadth = 5x cm and height = 4x cm

               ${\sf{Length \times breadth \times height =volume}$

                       ${\sf{ =>6x \times 5x \times 4x = 15,000}$

                  ${\sf{=> x^{3} = \dfrac{15,000}{6 \times 5 \times 4}=125= 5 \times 5 \times 5 = 5^{3}}$

⇒                        x = 5

${\sf{i.e. \: \: \: length =6x \: cm = 6 \times 5 \: cm= 30 \: cm}$

     ${\sf{breadth =5x \: cm = 5 \times 5 \: cm=25 \: cm}$

${\sf{and, \: height = 4x \: cm = 4 \times 5 \: cm=20 \: cm}$

(ii)  ${\sf{Surface \: area \: of \: the \: cuboid =2(l \times b+b \times h + h \times l)}$

                                            ${\sf{=2(30 \times 25+25\times 20 + 20 \times 30 ) cm^{2}}$

                                            ${\sf{2(750+500+600)cm^{2}=3700 \: cm^{2}$