Posted by jennie on Tuesday, January 25, 2011 at 11:41pm.
I am a third grader and have a homework of sketching and labeling all possible rectangles with perimeter of 30 cm and sides whose lengths are whole numbers. I am confuse, i need help please.

math  helper, Tuesday, January 25, 2011 at 11:47pm
The formula for perimeter is,
P = 2w + 2 L
30 = 2w + 2L
30 = 2(w + l)
15 = w + l
So, for a perimeter of 30, you want to sketch rectangles that the width and length total 15.
Some possible rectangles,
14 + 1 = 15
13 + 2 = 15
12 + 3 = 15
11 + 4 = 15
10 + 5 = 15
9 + 6 = 15
8 + 7 = 15
Do you follow what I am doing?
I gave you a good start. Find the remaining sides that when added, equal 15.
Good luck! :) 
math  jennie, Wednesday, January 26, 2011 at 12:10am
I will try. This will help me to start and gave me an idea. Thank you very much.

math  helper, Wednesday, January 26, 2011 at 12:20am
You're welcome.