130k views
3 votes
A rectangle has a perimeter of 18 cm. Its length is 5 cm greater than its width. Let l represent the length and w represent the width. Write a linear system and solve it to find the dimensions.

The length is 2 cm and the width is 7 cm.
The length is 6 cm and the width is 3 cm.
The length is 4 cm and the width is 5 cm.
The length is 7 cm and the width is 2 cm.

User Confuse
by
8.2k points

1 Answer

4 votes

Final answer:

To find the rectangle dimensions, a linear system is formed using the perimeter formula and the relationship between length and width. Upon solving, the rectangle's dimensions are determined to be a length of 7 cm and a width of 2 cm.

Step-by-step explanation:

Solving the Linear System for Rectangle Dimensions

Lets define the variables for the rectangle where l represents the length and w represents the width. Given that the perimeter of the rectangle is 18 cm, we can state the perimeter formula as 2l + 2w = 18. Additionally, we are told that the length is 5 cm greater than the width, which gives us the equation l = w + 5.

Now, we will use substitution to solve for the width and length:

  • Substitute l = w + 5 into the perimeter equation: 2(w + 5) + 2w = 18.
  • Simplify: 2w + 10 + 2w = 18.
  • Combine like terms: 4w + 10 = 18.
  • Isolate w: 4w = 18 - 10, which simplifies to 4w = 8.
  • Divide by 4: w = 2 cm.

Since we now know that w = 2 cm, we can find the length by substituting back into the equation l = w + 5:

  • Substitute w into the equation for l: l = 2 + 5.
  • Thus, l = 7 cm.

Therefore, the dimensions of the rectangle are: length is 7 cm and width is 2 cm.

User CMoi
by
8.8k points