Question

The length of hall is 10 m and breadth is twice its height. If the area of its four walls is 144 m2 find its volume

Answer 1

Length=10m
Breadth=2x
Height= x
Area of the four wall =2*h(l+b)
144 =2*x(10+2x)
144/2=x(10+2x)
72= 10x+2x²
72=12x²
x²=72/12
x=6


Breadth=2*6=12
Height=6
Volume=L*B*H
=10*12*6
=720m²

Answer 2

Answer:

the length of hall = 10m

the breadth of the hall = 2x

the height of the hall = x

the area of it's 4 walls = 144

LSA = 144

2(l+b)×h = 144

2(10+2x)x= 144

(20+4x)x= 144

20x+4x^2=144

4(x^2+5x)=144

x^2+5x=144÷4

x^2+5x= 36

x^2+5x-36=0

(by fractorisation )

x^2+(9-4)x - 36 =0

x^2 + 9x - 4x - 36 =0

x(x+9) -4(x+9)=0

(x+9)(x-4)= 0

the value of x will be 4 as -9 is negative

x=4

h=4

b=8

l=10

volume=l×b×h

=10×8×4

=320 m^2