## countonme123 3 years ago The perimeter of a rectangle field is 60 meters. Its area is 200 square meters. Find its dimensions.

1. countonme123

Please explain each step. I am having trouble here. :(

2. countonme123

come on guys there has to be at least one nerd here. lol

|dw:1340060211664:dw|

so you'll have to solve this system. From the second equation b=30-a so plug it back into the first equation and you'll get this equation:|dw:1340060339958:dw|

so your rectangle field has sides a=10 b=20 or a=20 b=10

do you understand this?

7. countonme123

ah so its that parenthese trick thing again where you multiply them and it equal a complicated equation? I think i get it

haha :D OK...you can think of it in that way...the basics are to know the formulas for area and perimeter of rectangle...then just to combine those two...I hope I helped you :D

9. countonme123

the only part i dont get is why you changed the 60 to 30

formula for the perimeter is 2(a+b) where a and b are lengths of sides...you have its value 60...so a+b=60/2=30...get it? :D

11. countonme123

ok got that ok what about the term you added after that?

a+b=30, so you can express one side by using the other side,so a=30-b....that's the connection between those two sides...so I plugged back 30-b instead of a in the first equation...that's how I got the quadratic equation which gives you the exact solution....

13. countonme123

hmmm, I still don't get why you added the term -a^2

how would you multiply a*(30-a)?

15. countonme123

why would you multiplay it by a? a^2 - 30a

16. countonme123

there must be something im missing cause i kinda get you...