1. **State the problem:** We are given a triangle with a mid-segment parallel to the base. The top side is labeled $4x$, the mid-segment is labeled 14, one side is labeled $7x - 9$, and the base is labeled 14. We need to find the value of $x$ using the converse of the mid-segment theorem.
2. **Recall the mid-segment theorem:** The mid-segment theorem states that the segment connecting the midpoints of two sides of a triangle is parallel to the third side and its length is half the length of that third side.
3. **Converse of the mid-segment theorem:** If a segment is parallel to one side of a triangle and its length is half the length of that side, then it connects the midpoints of the other two sides.
4. **Apply the theorem to the problem:** The mid-segment is given as 14, and the base is also 14. Since the mid-segment should be half the length of the base, but here both are equal, this suggests the mid-segment is not half but equal to the base. This implies the segment labeled 14 is not a mid-segment unless the triangle is degenerate or the labeling corresponds differently.
5. **Check the given segments:** The top side is $4x$, the mid-segment is 14, and one side is $7x - 9$. Since the mid-segment is parallel to the base (14), by the converse theorem, the mid-segment length should be half the base length.
6. **Set up the equation:** Since the mid-segment is 14 and the base is 14, the mid-segment should be half the base, so:
$$14 = \frac{1}{2} \times 14$$
This is false, so instead, the problem likely wants us to use the equality of the two segments labeled 14 to find $x$.
7. **Use the equality of the two segments labeled 14:** The mid-segment is 14, and the base is 14, so the mid-segment equals the base. This suggests the segment labeled $4x$ is equal to the mid-segment 14, and the segment labeled $7x - 9$ is equal to the base 14.
8. **Set up equations:**
$$4x = 14$$
$$7x - 9 = 14$$
9. **Solve the first equation:**
$$4x = 14$$
$$x = \frac{14}{4} = 3.5$$
10. **Check the second equation with $x=3.5$:**
$$7(3.5) - 9 = 24.5 - 9 = 15.5 \neq 14$$
11. **Since the second equation does not equal 14, check if the mid-segment theorem applies to the sides $4x$ and $7x - 9$:**
The mid-segment theorem states the mid-segment is half the base, so:
$$14 = \frac{1}{2} \times (7x - 9)$$
12. **Solve for $x$:**
$$14 = \frac{7x - 9}{2}$$
Multiply both sides by 2:
$$28 = 7x - 9$$
Add 9 to both sides:
$$37 = 7x$$
Divide both sides by 7:
$$x = \frac{37}{7} \approx 5.2857$$
13. **Verify $4x$ with this $x$:**
$$4 \times \frac{37}{7} = \frac{148}{7} \approx 21.14$$
This does not equal 14, so the segment labeled $4x$ is not equal to the mid-segment.
14. **Conclusion:** The value of $x$ that satisfies the mid-segment theorem using the side $7x - 9$ and the mid-segment 14 is:
$$\boxed{\frac{37}{7}}$$
Mid Segment X 2F2148
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.