Answer :
To solve the question regarding the perimeter of a rectangular pen with the given conditions, let's proceed step-by-step.
### Given:
1. Length = [tex]\( 2a \)[/tex] (twice the width)
2. Perimeter = 68
3. Width = [tex]\( a \)[/tex]
### According to the formula for the perimeter of a rectangle:
[tex]\[ P = 2(\text{Length} + \text{Width}) \][/tex]
### Substitute the known values:
[tex]\[ 68 = 2(2a + a) \][/tex]
### Simplify the equation inside the parentheses:
[tex]\[ 68 = 2 \cdot 3a \][/tex]
[tex]\[ 68 = 6a \][/tex]
### Solve for [tex]\( a \)[/tex]:
[tex]\[ a = \frac{68}{6} \][/tex]
[tex]\[ a = \frac{34}{3} \][/tex]
[tex]\[ a \approx 11.\overline{3} \][/tex]
### Given:
- Width = [tex]\( a \approx 11.\overline{3} \)[/tex]
- Length = [tex]\( 2a = 2 \times 11.\overline{3} = 22.\overline{6} \)[/tex]
### Verification of the Perimeter:
Substitute the length and width back into the perimeter formula to confirm:
[tex]\[ \text{Perimeter} = 2(\text{Length} + \text{Width}) \][/tex]
[tex]\[ \text{Perimeter} = 2(22.\overline{6} + 11.\overline{3}) \][/tex]
[tex]\[ \text{Perimeter} = 2 \times 34 = 68 \][/tex]
This is correct.
### Now, if [tex]\( a \)[/tex] represents the length of the rectangular pen:
Given:
1. Width = [tex]\( \frac{a}{2} \)[/tex]
2. Length = [tex]\( a \)[/tex]
3. Perimeter formula:
[tex]\[ P = 2(\text{Length} + \text{Width}) \][/tex]
[tex]\[ P = 2\left(a + \frac{a}{2}\right) \][/tex]
[tex]\[ P = 2\left(\frac{3a}{2}\right) \][/tex]
[tex]\[ P = 3a \][/tex]
Given that the perimeter is the same:
[tex]\[ 3a = 68 \][/tex]
Solve for [tex]\( a \)[/tex]:
[tex]\[ a = \frac{68}{3} \][/tex]
[tex]\[ a = 22.\overline{6} \][/tex]
So, when [tex]\( a \)[/tex] represents the length:
- Length = [tex]\( a \approx 22.\overline{6} \)[/tex]
- Width = [tex]\( \frac{a}{2} \approx \frac{22.\overline{6}}{2} = 11.\overline{3} \)[/tex]
### Conclusion:
When [tex]\( a \)[/tex] represents the length of the pen:
- The width is [tex]\( \frac{a}{2} \)[/tex].
- Using the formula for the perimeter, the relation [tex]\( P = 3a \)[/tex] explains that if the perimeter is 68, then the length [tex]\( a \)[/tex] would be [tex]\( 22.\overline{6} \)[/tex].
### Given:
1. Length = [tex]\( 2a \)[/tex] (twice the width)
2. Perimeter = 68
3. Width = [tex]\( a \)[/tex]
### According to the formula for the perimeter of a rectangle:
[tex]\[ P = 2(\text{Length} + \text{Width}) \][/tex]
### Substitute the known values:
[tex]\[ 68 = 2(2a + a) \][/tex]
### Simplify the equation inside the parentheses:
[tex]\[ 68 = 2 \cdot 3a \][/tex]
[tex]\[ 68 = 6a \][/tex]
### Solve for [tex]\( a \)[/tex]:
[tex]\[ a = \frac{68}{6} \][/tex]
[tex]\[ a = \frac{34}{3} \][/tex]
[tex]\[ a \approx 11.\overline{3} \][/tex]
### Given:
- Width = [tex]\( a \approx 11.\overline{3} \)[/tex]
- Length = [tex]\( 2a = 2 \times 11.\overline{3} = 22.\overline{6} \)[/tex]
### Verification of the Perimeter:
Substitute the length and width back into the perimeter formula to confirm:
[tex]\[ \text{Perimeter} = 2(\text{Length} + \text{Width}) \][/tex]
[tex]\[ \text{Perimeter} = 2(22.\overline{6} + 11.\overline{3}) \][/tex]
[tex]\[ \text{Perimeter} = 2 \times 34 = 68 \][/tex]
This is correct.
### Now, if [tex]\( a \)[/tex] represents the length of the rectangular pen:
Given:
1. Width = [tex]\( \frac{a}{2} \)[/tex]
2. Length = [tex]\( a \)[/tex]
3. Perimeter formula:
[tex]\[ P = 2(\text{Length} + \text{Width}) \][/tex]
[tex]\[ P = 2\left(a + \frac{a}{2}\right) \][/tex]
[tex]\[ P = 2\left(\frac{3a}{2}\right) \][/tex]
[tex]\[ P = 3a \][/tex]
Given that the perimeter is the same:
[tex]\[ 3a = 68 \][/tex]
Solve for [tex]\( a \)[/tex]:
[tex]\[ a = \frac{68}{3} \][/tex]
[tex]\[ a = 22.\overline{6} \][/tex]
So, when [tex]\( a \)[/tex] represents the length:
- Length = [tex]\( a \approx 22.\overline{6} \)[/tex]
- Width = [tex]\( \frac{a}{2} \approx \frac{22.\overline{6}}{2} = 11.\overline{3} \)[/tex]
### Conclusion:
When [tex]\( a \)[/tex] represents the length of the pen:
- The width is [tex]\( \frac{a}{2} \)[/tex].
- Using the formula for the perimeter, the relation [tex]\( P = 3a \)[/tex] explains that if the perimeter is 68, then the length [tex]\( a \)[/tex] would be [tex]\( 22.\overline{6} \)[/tex].