McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
3. Inequalities in One Triangle
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Exercise 53 Page 433

The centroid is the point of concurrency of the medians of a triangle. Use the Concurrency of Medians Theorem.

XK = 9

Practice makes perfect

The centroid is the point of concurrency of the medians of a triangle. In the given diagram, P is the centroid.

Using the Concurrency of Medians Theorem, we can write an equation that we can use to find the desired length XK. XP = 2/3XK With the Segment Addition Postulate, we can rewrite XK as the sum of the two smaller segments. We are given that KP= 3, which we can substitute into this new equation. XK = XP+ KP ⇒ XK = XP+ 3 Next, we can form a system of equations that we can solve using the Substitution Method.
XP = 23XK & (I) XK = XP+3 & (II)
XP = 23( XP+3) XK = XP+3
XP = 23XP+2 XK = XP+3
13XP = 2 XK = XP+3
XP = 6 XK = XP+3
Finally, we can substitute XP=6 into the second equation to find XK.
XP = 6 XK = XP+3
XP = 6 XK = 6+3
XP =6 XK = 9