Answer:
The dimensions are length 7 cm and width 21 cm.
Step-by-step explanation:
Given:
The rectangle shown has a perimeter of 56 cm.
It's length is 7 more than twice its width.
Now, to find the dimensions.
Let the width be [tex]x.[/tex]
And the length = [tex]7+2x.[/tex]
Perimeter = 56 cm.
Now, putting formula to get the dimensions:
[tex]Perimeter=2(length+width)[/tex]
[tex]56=2((7+2x)+x)[/tex]
[tex]56=2(7+2x+x)[/tex]
[tex]56=2(7+3x)[/tex]
[tex]56=14+6x[/tex]
Subtracting both sides by 14 we get:
[tex]42=6x[/tex]
Dividing both sides by 6 we get:
[tex]7=x\\x=7\ cm.[/tex]
So, the width = 7 cm.
And the length:
7+2[tex]x[/tex]
= 7 + 2\times 7
= 7 + 14
= 21 cm.
Therefore, the dimensions are length 7 cm and width 21 cm.