PDF chapter test TRY NOW

In right-angle triangle \(PQR\), what is the length of altitude drawn from the vertex \(P\) to \(QR\) if \(PR = 85\) units and \(QR = 84\) units?
 
EX_2.1.png
 
The vertex drawn from the \(P\) to \(QR\) is  units.