SOLUTION: Triangle PQR is right angled at Q. QT is perpendicular to PR, where T is the point on PR. If PQ = 3cm and PR = 18cm. Find QT

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Question 1132554: Triangle PQR is right angled at Q. QT is perpendicular to
PR, where T is the point on PR. If PQ = 3cm and PR =
18cm. Find QT
Answer by ikleyn(52824) About Me  (Show Source):
You can put this solution on YOUR website!
.
You can calculate the area of the triangle PQR by two ways.


One way is      Area = 1%2F2.abs%28PQ%29.abs%28QR%29.


Another way is  Area = 1%2F2.abs%28PR%29.abs%28QT%29.


Since the area is the same, it gives you an equation


    1%2F2.abs%28PQ%29.abs%28QR%29 = 1%2F2.abs%28PR%29.abs%28QT%29,   or   abs%28PQ%29.abs%28QR%29 = abs%28PR%29.abs%28QT%29.


Hence,  |QT| = %28abs%28PQ%29%2Aabs%28QR%29%29%2Fabs%28PR%29 = %283%2A18%29%2Fsqrt%283%5E2%2B18%5E2%29 = %283%2A18%29%2F%283%2Asqrt%281%5E2%2B6%5E2%29%29 = 18%2Fsqrt%2837%29 = 3.959 (approximately; correct with 3 decimal places).       ANSWER

Solved.