What is the value of the inradius of triangle $PHQ$? For refrence: The right triangle $ABC$, right at $B$, the height $BH$ is drawn. Let $P$ and $Q$ be the intersections of triangles $AHB$ and $BHC$,
$PQ$ intersects at $E$ the $BH$, where $\frac{BE}{EH} = 5\sqrt2$ and the inradius of the triangle $ABC$ measures $10$.
Calculate the inradius of triangle $PHQ$.(Answer: $1$)
My progress..It is a complicated drawing ..not to scale...
I found it a difficult question and didn't get much out of it.... Maybe there is some relationship between the inradius but I don't know
I I know this(by property): $ r_1+r_2+R = BH\\
r_1+r_2+10 = BH$
Also: $\triangle MPH \sim \triangle NQH \implies\\
\frac{r_1}{r_2} = \frac{PH}{QH}$
By Geogebra $\triangle PQH$ is right?? $\implies$ T.Poncelet: $PH+HQ = PQ+2r$
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$S$ the point of touching incircle ABH with BH. $T$ is the point of intersection of straight lines $PS$ and $QN$. Triangles $PES$ and $PQT$ are right and similar. $PS=r_1$, $PT=r_1+r_2$, $QT=r_2-r_1$. From similarity:
$$ES=PS\cdot QT/PT=r_1\frac{r_2-r_1}{r_1+r_2}$$
$$EH=ES+SH=r_1\frac{r_2-r_1}{r_1+r_2}+r_1=\frac{2r_1r_2}{r_1+r_2}$$
From similarity of triangles $AHB$, $CHB$ and $ABC$ and Pythagoras theorem follows $$R^2=r_1^2+r_2^2\Rightarrow 2r_1r_2=(r_1+r_2)^2-R^2\Rightarrow EH=r_1+r_2-\frac{R^2}{r_1+r_2}$$
$$BH=BE+EH=5\sqrt{2}\cdot EH+EH=EH(5\sqrt{2}+1)$$
Also $BH=r_1+r_2+R$, then
$$r_1+r_2+R=\left(r_1+r_2-\frac{R^2}{r_1+r_2}\right)(5\sqrt{2}+1)$$
Let $r_1+r_2=xR$, then
$$x+1=\left(x-\frac{1}{x}\right)(5\sqrt{2}+1)\Rightarrow x=(x-1)(5\sqrt{2}+1)\Rightarrow x=1+\frac{\sqrt{2}}{10}$$
The incircle radius of tectangular triangle $PHQ$ is $$\frac{PH+HQ-PQ}{2}=\frac{r_1\sqrt{2}+r_2\sqrt{2}-\sqrt{2r_1^2+2r_2^2}}{2}=R\sqrt{2}\ \frac{x-1}{2}=\frac{R}{10}=1$$
The answer will transform to 2 if one changes $5\sqrt{2}$ to $\frac{5}{\sqrt{2}}$.
