In triangle PQR, PQ = 13, QR = 14, and PR = 15. Let M be the midpoint of QR. Find PM.
+1005 From Herons formula we have the area as
\([PQR] = \sqrt{(21)(21-13)(21-14)(21-15)} = \sqrt{(21)(8)(7)(6)} = 7\cdot 3\cdot 4 = 84.\)
\([PQR] = \frac12(QR)(PH) = 7PH\)
Does this help?
