Is I have a rectangular prism which basis area is 12 cm^2 and height 8 cm, then calculate the values of "a" and "b" where "a" and "b" are basis dimensions... The best medal ever
@pooja195
a rectangular prism has a base of rectangle area of a rectangle is ??? do you know this formula ?
area= a*b
exactly so you need getting two integers a and b with product equal 12
ok. one choice may be 12 = 3*4 right ?
look at that image
I need to find Lateral area, total area and volume
this image dont change nothing for you get this a and b
I found volume value which is 96 cm^3
yes sure this was easy bc. V = area of base time height so = 12*8 = 96 cm^3
12= 6*2 12= 4*3 12= 12*1 12= 2sqrt(3)*2sqrt(3)
2sqrt3 not can being bc. this is a rectangle not a square
I already know the answers, but I just wanna know how to get the answer no making assumptions
and so the a need being different the b
do you get me?
that's right! a is different than b
bc. in this text of your exercise given just these details so there are much possibility how you ve wrote above 3*4 6*2 12*1
Could you find a formula that relates basis area with that basis rectangle perimeter?
why ? do you know the perimeter too ?
area = a*b perimeter = 2(a+b)
I don't xD... That's why I want to find that formula... I already have the area value
I guess that the only way to solve this exercise is by making assumptions of "a" and "b" values
don't you think?
ok. a*b = 12 => a = 12/b P = 2a +2b =2*(12/b) +2b do you think it so ?
\[perimeter = \frac{ 24 }{ b }+2b\] \[perimeter = \frac{ 24+2b^2 }{ b }\] \[b*perimeter=24+2b^2\] \[2b^2-b*perimeter+24=0\] \[b=\frac{ perimeter ∓ \sqrt{(-perimeter)^{2}-4*2*24}}{ 4 }\]
I still have an unknow value which is perimeter... @jhonyy9
your statement is incomplete. dimensions of base may be 1*12,2*6,3*4 if a and b are integers. a*b=12 p=2(a+b) =2(1+12)=26 or =2(2+6)=16 or =2(3+4)=14 if a and b are real numbers ,then there are infinite real numbers (a neq 0,b neq 0) such that ab=96 a=96/b p=2(a+b)=2((96/b)+b)
in your case b is real so\[P^2-4*2*24 \geq 0\] \[P^2 \geq 4*16*3\] \[\left| P \right|\geq 8\sqrt{3}\] so \[P \leq-8\sqrt{3}~or P \geq 8\sqrt{3}\] perimeter can not be negative Hence \[P \geq 8\sqrt{3}\] so minimum value of perimeter is\[8\sqrt{3}\]
thanks a lot @sshayer :)
correction write 12 in place of 96
yw
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