Angles and Midpoints

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Thanic Nur Samin
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Angles and Midpoints

Unread post by Thanic Nur Samin » Sat Jan 14, 2017 11:33 am

Let $B$ and $C$ be two points and $M$ be their midpoint. Let $X$ be also a point on the same plane. Define $T$ to be a point so that $\angle XMT=90^{\circ}$ and $XB=XT$ which lies inside the circumcircle of $BMX$. Prove that, $\angle TXB=2\angle MTC$.
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Thanic Nur Samin
Posts:176
Joined:Sun Dec 01, 2013 11:02 am

Re: Angles and Midpoints

Unread post by Thanic Nur Samin » Sat Jan 14, 2017 11:55 am

Let $N$ denote the midpoint of $BT$. So, $\angle TNX=90^{\circ}, \angle TMX=90^{\circ}$. So $TNMX$ is cyclic. Now, $\dfrac{1}{2}\angle BXT=\angle TXN=\angle TMN$. Since $M$ and $N$ are midpoints of $BC$ and $BT$ respictively, $MN\parallel CT$, so we get $\angle TMN=\angle MTC$, therefore $\angle BXN=2\angle CTM$.
Hammer with tact.

Because destroying everything mindlessly isn't cool enough.

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