Hi.
Formula for area: A = 2l + 2w, where l is the length and w is the width.
Given information:
• l = 2w - 1
• A = 21 in^2
We can plug in our values accordingly and solve for w.
A = 2l + 2w
21 = 2(2w - 1) + 2w
21 = 4w - 2 + 2w
23 = 6w - 2
23 = 6w
3.83 = w
Plug 3.83 for w into 2w - 1 to find length.
2(3.83) - 1
7.66 - 1
6.66
Finally, check your work by plugging your values into the original equation.
21 = 2(6.66) + 2(3.83)
21 = 13.32 + 7.66
21 = 20.98
Answer:
The length is approximately 6.66 inches.
