Here’s the completion of the proof that the three medians of a triangle intersect at a single point \( P \) using the given steps and incorporating the appropriate responses:
Step 1:
Draw the three medians of the triangle. Draw each median so that it starts at a vertex and ends at the midpoint of the opposite side.
Step 2:
Find the coordinates of each midpoint by taking the sum of the x-coordinates and dividing by 2 and taking the sum of the y-coordinates and dividing by 2.
- The midpoint between (0, 0) and (b, c) is \(\left(\frac{b}{2}, \frac{c}{2}\right)\).
- The midpoint of (0, 0) and (a, 0) is \(\left(\frac{a}{2}, 0\right)\).
- The midpoint of (a, 0) and (b, c) is \(\left(\frac{a+b}{2}, \frac{c}{2}\right)\).
Step 3:
Find the coordinates of \( P \), the point where the medians appear to intersect, on each median. Use the formula \(\frac{1}{3}\left(\text{coordinates of vertex}\right)+\frac{2}{3}\left(\text{coordinates of midpoint}\right)\).
Step 4:
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Find the coordinates of \( P \) on the median that starts at vertex (0, 0) and ends at midpoint \(\left(\frac{a+b}{2}, \frac{c}{2}\right)\). \[ P=\frac{1}{3}(0, 0) + \frac{2}{3}\left(\frac{a+b}{2}, \frac{c}{2}\right) = \left(\frac{a+b}{3}, \frac{c}{3}\right) \]
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Find the coordinates of \( P \) on the median that starts at vertex (a, 0) and ends at midpoint \(\left(\frac{b}{2}, \frac{c}{2}\right)\). \[ P=\frac{1}{3}(a, 0) + \frac{2}{3}\left(\frac{b}{2}, \frac{c}{2}\right) = \left(\frac{a+b}{3}, \frac{c}{3}\right) \]
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Find the coordinates of \( P \) on the median that starts at vertex (b, c) and ends at midpoint \(\left(\frac{a}{2}, 0\right)\). \[ P=\frac{1}{3}(b, c) + \frac{2}{3}\left(\frac{a}{2}, 0\right) = \left(\frac{a+b}{3}, \frac{c}{3}\right) \]
Step 5:
The coordinates of \( P \) on each median are \(\left(\frac{a+b}{3}, \frac{c}{3}\right)\), which proves that the three medians of this generic triangle all intersect at the same point.
This completes the proof that the medians of a triangle meet at a single point, known as the centroid.