Art of Problem Solving

Power of a Point Theorem/Introductory Problem 1: Difference between revisions

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== Solution ==
== Solution ==


Applying the Power of a Point Theorem gives us <math> 3\cdot(3+5) = x (x+10) </math>.  Expanding and simplifying we get <math> x^2 + 10x - 24 = 0 </math>.  This factors as <math> (x+12)(x-2) = 0 </math>.  We discard the negative solution since distance must be positive.  Thus <math> x=2 </math>.
Applying the [[Power of a Point Theorem]], we get <math> 3\cdot(3+5) = x (x+10) \rightarrow x^2 + 10x - 24 = 0 </math>.  This factors as <math> (x+12)(x-2) = 0 </math>.  We discard the negative solution since distance must be positive.  Thus <math> x=2 </math>.


''Back to the [[Power of a Point Theorem]].''
''Back to the [[Power of a Point Theorem]].''

Revision as of 22:25, 1 January 2020

Problem

Find the value of $x$ in the following diagram:

Solution

Applying the Power of a Point Theorem, we get $3\cdot(3+5) = x (x+10) \rightarrow x^2 + 10x - 24 = 0$. This factors as $(x+12)(x-2) = 0$. We discard the negative solution since distance must be positive. Thus $x=2$.

Back to the Power of a Point Theorem.