Question 195 of 480
Find the midpoint of the line joining P(-3, 5) and Q(5, -3).
- A. (1, 1)
- B. (2, 2)
- C. (4, 4)
- D. (4, -4)
Correct Answer:
A
Explanation
To find the midpoint of the line segment joining two points \( P(-3, 5) \) and \( Q(5, -3) \), we can use the midpoint formula. The midpoint \( M \) of a line segment connecting two points \( (x_1, y_1) \) and \( (x_2, y_2) \) is given by the formula:
\[
M = \left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right)
\]
### Step-by-Step Calculation
1. **Identify the coordinates of the points**:
- Point \( P \) has coordinates \( (x_1, y_1) = (-3, 5) \)
- Point \( Q \) has coordinates \( (x_2, y_2) = (5, -3) \)
2. **Substitute the coordinates into the midpoint formula**:
- For the x-coordinate of the midpoint:
\[
x_M = \frac{x_1 + x_2}{2} = \frac{-3 + 5}{2}
\]
\[
x_M = \frac{2}{2} = 1
\]
- For the y-coordinate of the midpoint:
\[
y_M = \frac{y_1 + y_2}{2} = \frac{5 + (-3)}{2}
\]
\[
y_M = \frac{5 - 3}{2} = \frac{2}{2} = 1
\]
3. **Combine the results**:
- The coordinates of the midpoint \( M \) are \( (1, 1) \).
### Conclusion
Thus, the midpoint of the line segment joining points \( P(-3, 5) \) and \( Q(5, -3) \) is \( (1, 1) \).
### Explanation of Options
- **Option A: (1, 1)** - This is the correct answer as we calculated the midpoint accurately.
- **Option B: (2, 2)** - This option is incorrect. It does not match our calculated midpoint.
- **Option C: (4, 4)** - This option is also incorrect. The coordinates do not correspond to the midpoint derived from the given points.
- **Option D: (4, -4)** - This option is incorrect as well. The coordinates do not reflect the midpoint calculation.
### Common Pitfalls
- **Miscalculating the sum of coordinates**: Ensure you add the x-coordinates and y-coordinates correctly.
- **Forgetting to divide by 2**: The midpoint formula requires averaging the coordinates, which means dividing by 2.
- **Confusing the order of points**: The order of points does not affect the midpoint, but itβs essential to keep track of which coordinates belong to which point.
### Revision Summary
- The midpoint formula is \( M = \left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right) \).
- To find the midpoint, add the x-coordinates and y-coordinates separately, then divide each sum by 2.
- The correct midpoint for points \( P(-3, 5) \) and \( Q(5, -3) \) is \( (1, 1) \).
- Always double-check your calculations to avoid common mistakes.