## kimye21 3 years ago The length of a rectangle is 7 inches more than the width. The perimeter is 42 inches. Find the length and width

1. kimye21

|dw:1348706471681:dw|

2. dpflan

Cool, so for that rectangle, perimeter is 42. How do you find the perimeter?

3. dpflan

Do you know the formula for finding the perimeter of an object?

4. kimye21

i think its p=2l+2w

5. dpflan

yeah, in this case for the rectangle, P = 2*length + 2*width. So you have values for the length and the width, right? L = x + 7 W = x

6. dpflan

Plug those values into the perimeter function, what does the equation look like after doing that?

7. kimye21

my equation looks like this 42=2(7)+2w 42-14=28 which makes w = 14 then for L 14+7=21 am i right

8. dpflan

Getting there, so the values you have for each dimension are actually variables - (x+7), and x Therefore P = 2*L + 2*W becomes L = x + 7 W = x P = 2*(x+7) + 2*(x) 42 = 2*(x+7) + 2*(x)

9. dpflan

Because there is only one variable, one unknown, that being 'x', we can easily then solve for it from the adjusted equation.

10. dpflan

Does that make sense? Give that equation a shot, and solve for x.

11. kimye21

x=7

12. dpflan

Definitely! that's it, so L = ? and W = ?

13. dpflan

Just have to do that last step and you're donw

14. dpflan

Quite easy after finding x...

15. kimye21

so w = 7 and l=14

16. dpflan

Nice work

17. kimye21

thanks