An irregular hexagon has a perimeter of \(50\,\text{cm}\). Four sides measure \(6\,\text{cm}\), \(8\,\text{cm}\), \(10\,\text{cm}\), and \(12\,\text{cm}\). The other two sides have equal lengths. A student says the missing sides can be \(6\,\text{cm}\) and \(8\,\text{cm}\) because those lengths total \(14\,\text{cm}\). Explain the error and find the two missing side lengths.
Hints
- A correct pair must satisfy both the perimeter total and the equal-length condition.
- Find the unused perimeter and divide it into two equal parts.
Solution
1. The four known sides total \(6 + 8 + 10 + 12 = 36\,\text{cm}\).
2. The two missing sides must total \(50 - 36 = 14\,\text{cm}\).
3. The proposed lengths \(6\,\text{cm}\) and \(8\,\text{cm}\) have the correct total, but they do not satisfy the condition that the two sides are equal.
4. Splitting \(14\,\text{cm}\) equally gives \(14 \div 2 = 7\,\text{cm}\) for each side.
Answer
The student's lengths have the correct total but are not equal. The missing sides are \(7\,\text{cm}\) and \(7\,\text{cm}\).