Question: 22. ★ SHORT RESPONSE A farmer plans to build a fence around a rectangular pen that is 16 feet long. The area of the pen is 80 square feet. Is 40 feet of fencing enough to fence in the pen? Explain.
1. **State the problem:**
A farmer wants to build a fence around a rectangular pen that is $16$ feet long. The area of the pen is $80$ square feet. We need to determine if $40$ feet of fencing is enough to enclose the pen.
2. **Identify known values:**
Length $L = 16$ feet
Area $A = 80$ square feet
Perimeter $P = ?$ (to check if $40$ feet is enough)
3. **Find the width $W$ of the pen using the area formula:**
$$A = L \times W$$
$$80 = 16 \times W$$
Divide both sides by 16:
$$\cancel{16} W = \frac{80}{\cancel{16}}$$
$$W = 5$$ feet
4. **Calculate the perimeter $P$ of the rectangle:**
$$P = 2(L + W)$$
$$P = 2(16 + 5)$$
$$P = 2(21) = 42$$ feet
5. **Compare the perimeter to the available fencing:**
The farmer has $40$ feet of fencing.
The required fencing is $42$ feet.
6. **Conclusion:**
Since $40 < 42$, $40$ feet of fencing is not enough to fence in the pen.
**Final answer:** No, $40$ feet of fencing is not enough because the perimeter of the pen is $42$ feet.