Areas and Perimeters

• Jul 5th 2012, 02:47 AM
Subliminalmessage
Areas and Perimeters
I've got psychometric test coming up and I've just realized that in the numeracy reasoning section, I will most likely have a question or two about areas and perimeters, I've got one example question which might give you an idea of the difficulty I will be faced with (not much to you I doubt) it will be multiple choice but I guess knowing the answer for sure is best.

If the perimeter of the square is 20cm, then the area of the square, in square centimetres is?

So could you tell me how to work this out?

Also, give me a short list of things I should know about squares, perimeters, shape and all that jazz. Times like these I really wish I studied in School.

Oh and I'm sorry, this is like my 4th or so post, if you guys have a problem with this like if it is spam or something please tell me but your help has been really great drink water so far.

Thanks.
• Jul 5th 2012, 02:50 AM
Prove It
Re: Areas and Perimeters
To get the area of a square, you would square its side length. So to get the side length from the area, you do the exact opposite process, i.e. take the square root of the area.
• Jul 5th 2012, 03:55 AM
daigo
Re: Areas and Perimeters
If you haven't learned about squares and roots yet, you might have an easier time knowing that the sides of a square are all the same, so divide the perimeter evenly between 4 sides (i.e. 20 / 4) and you should get the length of one side, which is the same as the length of all the sides (since it's a square).

Then the general area of a rectangle (a square is just a special rectangle that has all of the same sides) is length multiplied by width, so just multiply the length by the width and that's your area (for a square it's just one side multiplied by any other side, since all the sides are the same, it doesn't matter which sides you use).
• Jul 6th 2012, 03:24 AM
Subliminalmessage
Re: Areas and Perimeters
Quote:

Originally Posted by daigo
If you haven't learned about squares and roots yet, you might have an easier time knowing that the sides of a square are all the same, so divide the perimeter evenly between 4 sides (i.e. 20 / 4) and you should get the length of one side, which is the same as the length of all the sides (since it's a square).

Then the general area of a rectangle (a square is just a special rectangle that has all of the same sides) is length multiplied by width, so just multiply the length by the width and that's your area (for a square it's just one side multiplied by any other side, since all the sides are the same, it doesn't matter which sides you use).

So, rectangle's side aren't all the same so how do I work out how long the length is and the width?
• Jul 6th 2012, 03:37 AM
daigo
Re: Areas and Perimeters
Usually the 'length' is referred to as the longest side, and the 'width' is the shorter side
• Jul 6th 2012, 04:52 AM
Subliminalmessage
Re: Areas and Perimeters
Okay, so can you give me an example question on a rectangle?
• Jul 6th 2012, 06:19 AM
HallsofIvy
Re: Areas and Perimeters
If rectangle R has area 35 square meters and perimeter 24 meters, what are its length and width.

The area of a rectangle is equal to "length times width" and its perimeter is equal to "twice the length plus twice the width".

So if you call the width "W" and the length "L", those say area= LW= 35 and perimeter= 2L+ 2W= 24. One way to solve for L and W is: divide the latter equation by L+ W= 12. The subtract L from both sides- W= 12- L. Replace W in LW= 35 by that- L(12- L)= 35. That is the same as the quadratic equation $L^2- 12L+ 35= 0$.
• Jul 25th 2012, 03:08 AM
kraj8995
Re: Areas and Perimeters
Its very simple.The perimeter of square is 20 cm.So its side is
side=20/4=5 cm.
Area of square = 5*5=25 square cm.
Mensuration is my favorite topic of mathematics and questions related to cuboid and cube are my favorite.