Find the dimensions of the rectangle whose length is three times its width and whose area is 48 square feet.

Question

anonymous · Answer

@Directrix  Hey, sorry to bug you again, but i really need help with this.

terenzreignz · Answer

Make do with me instead, for now :)
Suppose we let w be the width of the rectangle... what's its length?
Remember, that the length is three times the width.

anonymous · Answer

If the width is w, and the length is 3 times the width, 3w right?
@terenzreignz

terenzreignz · Answer

Correct.  Now, the area of a rectangle is the length times the width, right?
And the width is w, the length is 3w, what's the area?

anonymous · Answer

3w times w=area  
right?

terenzreignz · Answer

Yeah.. so, whats w times 3w?

anonymous · Answer

4w?

terenzreignz · Answer

No... that's w PLUS 3w.
w times 3w = 3w²
right?

anonymous · Answer

Oh, right hah sorry! okay so the area is 3w^2?

terenzreignz · Answer

Yep.  But the area is also given to be 48...
So you have
3w² = 48
Can you solve for w?

terenzreignz · Answer

Solved for w yet?

anonymous · Answer

3w^2=48
w=4 right? or -4?

terenzreignz · Answer

Yeah... but can a width ever be negative? :)

anonymous · Answer

haha good point! Thanks for all the help:)

terenzreignz · Answer

Finish it though...
Your width w = 4
What's your length?

anonymous · Answer

length-12
width-4
area-48 right?

terenzreignz · Answer

Okay, a job well done :)

anonymous · Answer

Thanks to a great teacher! :)