In an acute triangle
, let
,
,
be the feet of the perpendiculars from the points
,
,
to the lines
,
,
, respectively, and let
,
,
be the feet of the perpendiculars from the points
,
,
to the lines
,
,
, respectively.
Prove that
, where
denotes the perimeter of triangle
.
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In an acute triangle $ABC$, let $D$, $E$, $F$ be the feet of the perpendiculars from the points $A$, $B$, $C$ to the lines $BC$, $CA$, $AB$, respectively, and let $P$, $Q$, $R$ be the feet of the perpendiculars from the points $A$, $B$, $C$ to the lines $EF$, $FD$, $DE$, respectively.
Prove that $p\left(ABC\right)p\left(PQR\right) \ge \left(p\left(DEF\right)\right)^{2}$, where $p\left(T\right)$ denotes the perimeter of triangle $T$ .