Find the sum of length, breadth & height of a cuboid whose whole surface area is 214 cm 2 , with a base area of 42 cm 2 , and with volume 210 cm 3 .
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
This is my opinion... Okay, you already know what is the sum of the length and width, and the value of the height, why don't you just add them up? This can save your time a little bit.
that's what you called a very long process but I understand
I have solved the same way but nice solution and representation !
easy way is lbh=210,lw=42,by solving these two we get h=5,which leaves lw=42 which must be 7*6 so l=7,b=6 so l+w+h=5+6+7=18
length = L
breadth = B
height = H
area of base = B * H
42 = B * H .........................(i)
volume = B * H * L
210 = (B * L) * H
210 = 42 * H [ from (i)]
H = 5
surface area = 2(L B + B H + H*L)
214 = 2(42 + 5B + 5L)
5B + 5L + 42 = 107
5(B + L) = 65
B + L = 13
Therfore,
H + B + L = 5 +13
=18
What happened to your LaTeX?
this is how i solved
Let l represent the length, b represent the breadth and h represent the height of the cuboid.
Then we can derive the following equations based on the information provided.
1) lbh = 210
2) 2lb + 2lh + 2bh = 214
3) lb = 42
Afterwards, use simultaneous equations to find out the individual values of l,b and h. From equations 1 and 3, we can find h by this formula: h= lbh/lb = 210/42 = 5.
Then, from equation 2, we can simplify it to become lb + lh + bh =107, then substitute the value of h into the newly derived equation, which will become lb + 5l + 5b = 107.
Since lb = 42 from equation 3, we can safely conclude that 5l + 5b =107 -42 = 65.
Then factorize out the common factor 5 to get 5(l + b) = 65.
In the end, we should get l+b = 13. Then just add 13 to 5 to get 18, which is the sum of the lengths of the cuboid. Simple! :)
Let length = l Breadth=b Height=h. Total Surface area of a cuboid=2(lb+lh+bh). lb=42(given) So by substituting the value of lb in the equation of total surface area we get h(l+b)=65. We know lbh=Total volume=210(given) We know that h=65/(l+b). Therefore by subs. the value of h in volume formula we get l+b=13 therefore l+b+h=18.
can someone explain with diagram??
2(lb + bh+ hl) = 214 ...... (1) lb = 42 ........(2) lbh = 210 ....... (3)
using (2) & (3), h = 5 substituting the values in (1), we get l + b = 13 so, l+b+h = 13 + 5 = 18
2(lb+bh+lh)=214 lb+bh+lh=214/2=107. Base area=lb=42. lb+bh+lh=107 bh+lh=107-42(lb=42) h(l+b)=65. Volume=lbh=210. volume/base area=lbh/lb=h h=210/42=5. h(l+b)=65 (l+b)5=65(h=5) l+b=65/5=13. l+b=13;h=5; l+b+h=13+5=18(Answer).
assume: l-length b-breadth h-height given lbh=210...............Eq.1 lb=42....................Eq.2 2(lb+bh+hl)=214.....Eq.3
eq.2/eq.1implies h=5 substitute h=5 in eq.3 that implies 2(42+5(l+b))=214 (l+b)=13 l+b+h=13+5=18
xy = 42 & xyz = 210 ==> z = 5 2xy + 2xz + 2yz = 214 <=> 2(42) + 10x + 10y = 214 <=> x + y = 13 <=> (42/y) + y = 13 <=> y^2 - 13y + 42 = 0 <=> x = 6 or 7 ==>y = 42/6 or 42/7 = 7 or 6 So (x+y+z) = 6+7+5 = 18 or (x+y+z) = 7+6+5 = 18
I solved it indirectly... I take volume and divide it by base area. I get 5. So, H = 5. Then I split base area as 6 x 7. Which is value nearer to height value. So, I take 5, 6, 7 as l,b,h. So, l+b+h = 18 :)
whole surface area 2(ab+bc+ca)=214 area of base ab=42 Volume abc=210 42.c=210 c=5 ab+bc+ca=107 42+5(a+b)=107 on solving a+b+13 a+b+c=13+5 =18
the surface area is given in the formula 2lw+2lh+2wh=214 (1) the base area is lxw=42 cm²(2) and the volume is lxwxh= 210 cm3 since the base is l x w we can now get the height by dividing the volume (210) by the area of the base(42) 210cm3/42cm²=5cm=h substitute h in eq.1 2lw+2lh+2wh=214 2lw+10l+10w=214(3) now tAke the value of w from the second eq. w=42/l substitute it in eq. (3) 2l(42/l)+10l+10(42/l)=214 84+10l+420/l=214l 10l²-130l+420=0 divide by common factor w/c is ten then factor l²-13l+42=0 (l-6)(l-7) l=7 w=6 h=5 add up and it's 18
we know, volume = area of base * height 210 = 42 * h
h = 5 cm
Now, Total Surface Area = 214
2(lb + bh + lh) = 214
Substituting h = 5,
2(lb + 5b + 5l) = 214
lb + 5b + 5l = 214/2 = 107
Since base area = length * breadth = 42,
Substituting the value of lb = 42,
42 + 5(b + l) = 107
5(l+b) = 107-42 = 65
l+b = 65/5 = 13
Now we have l+b = 13
Add h=5 on both sides,
l+b+h = 13+h = 13+5 = 18cm
Answer = 18 cm
we have, 2(lb+bh+hl)=214 ........(1),
l
b
h=210 ..............(2),
l*b=42 ...(3)
from (2) & (3) we get,
h=5.
put the value of h in ...(1).
hence, we get (l+b)=13.
so, l+b+h=18
Volume = b a s e a r e a × h e i g h t . Height = 4 2 2 1 0 = 5.
Surface area = 2(lb+lh+bh) = 214
lb+lh+bh = 107
But lb = 42... Therefore, lh+bh= 65.
But h = 5, therefore, 5(l+b)=65
l+b=13
Hence, l+b+h = 13+5 =18
First, equate lxw=42 which is the base area, then The total surface area which is 214= 2(lw+wh+lh) and the third equation is the volume 210=lxwxh. L=42/w 214= 2(lw+wh+lh) 107=lw+wh+lh 107=42/w(w)+wh+42/w(h) 65=wh+42/w(h) H=65w/w2+42 210=42/w(w)( 65w/w2+42) W2-13w+42=0 W=6 or 7 L=6 or 7 H=5 W+h+l=18
Let's say length, breadth and height are l,b,h resp. now, we have l b h=210 (volume of cuboid) l b =42 (base area of cuboid) substituting l b in above eq we get h=5; now total surface area of a cuboid is 2 (l b+b h+h l) = 214 (given) soving and subs known values we get sum =18
Let the length, breadth and height of the cuboid be l , b , h respectively. We know that Area of Base = l b , Volume of the cuboid = l b h and Total Surface Area of Cuboid = 2 ( l b + b h + l h ) .
GIven that, l b = 4 2 . . . ( i ) and l b h = 2 1 0 . . . . ( i i )
Dividing (ii) by (i), we get, l b l b h = 4 2 2 1 0 ⟹ h = 5
So now we have the height, h=5 cm. Now, we have ---
2 ( l b + b h + l h ) = 2 1 4
⟹ 2 ( l b + h ( l + b ) ) = 2 1 4
⟹ 2 ( 4 2 + 5 ( l + b ) ) = 2 1 4 ⟹ 8 4 + 1 0 ( l + b ) = 2 1 4 ⟹ 1 0 ( l + b ) = 1 3 0 ⟹ l + b = 1 3
So, Sum of l , b , h = l + b + h = ( l + b ) + h = 1 3 + 5 = 1 8 cm
l,b,h.. 7,6,5 .... 18 do math
and one more way .. lbh=210 and lb+bh+lh=214 ....... eq2/eq1 ... also leads same
Let a,b and c be the length,breadth and height.
Its given ab=42 and abc=210, so c=5
Also given that 2(ab+bc+ca)=214
i.e ab+bc+ca=107
c(b+a)=65,since ab=42
a+b=13,c=5
So a+b+c=18
Let a,b,h be the length, breadth and height of the cuboid respectively. Thus from given Total surface area, 2(ab+bh+ha)=214 Base area, ab=42 Volume, abh=210
Solving we get, h=5 and a+b=13
thus, the required answer is 18
2 ( l x b ) + 2 ( h x b) + 2 ( l x h) = 214SqCm l x b = 42 SqCm & l x b x h= 210CuCm
Now the solution
42x h = 210 --- h = 210/42= 5Cm
2 x 42 + 2 x 5 b + 2 x 5 x l =214 10(l + b ) = 214- 84= 130 ( l + b ) = 13
Hence l +b+h= 13+5 = 18Cm
Problem Loading...
Note Loading...
Set Loading...
The whole surface: 2 ( l w + l h + w h ) = 2 1 4
( l w + l h + w h ) = 1 0 7
4 2 + h ( l + w ) = 1 0 7
h ( l + w ) = 6 5
volume= 210
l w h = 2 1 0
( 4 2 ) h = 2 1 0
h = 5
5 ( l + w ) = 6 5
l + w = 1 3
l = 1 3 − w
l w = 4 2
( 1 3 − w ) . w = 4 2
w 2 − 1 3 w + 4 2 = 0
( w − 6 ) ( w − 7 ) = 0
w = 6 or w = 7
l = 1 3 − w
l = 7 or l = 6
So, the sums of length, width, and height is 6+7+5= 18