In triangle \(\triangle{PQR}\), we have \(\angle P = 90^\circ\), \(QR = 20\), and \(\tan R = 4\sin R\). What is \(PR\)?
This is a right-angled triangle with QR as the hypotenuse. Let PQ be the Opposite to angle at R, and PR be the Adjacent.
tanR = 4sinR means 1/cosR = 4, or cosR = 1/4
But cosR = PR/QR = PR/20
So PR/20 = 1/4
Hence PR = 5
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