Question 15
Circles with centers $P,$ $Q,$ and $R,$ having radii $1,$ $2,$ and $3,$ respectively, lie on the same side of line $l$ and are tangent to $l$ at $P',$ $Q',$ and $R',$ respectively, with $Q'$ between $P'$ and $R'.$ The circle with center $Q$ is externally tangent to each of the other two circles. What is the area of $\triangle PQR?$