In triangle PQR, right angled at Q, PR$+$QR=25cm and PQ=5cm.Determine the values of sinP, cosP, tanP.


Given: In triangle PQR, right angled at Q, PR$+$QR=25cm and PQ=5cm

To do: Determine the values of sinP, cosP, tanP.


Answer:

In the triangle let QR =$x$; PR $+$ QR = 25 (given); then PR = 25 $- x$

PQ = 5 cm (given)

Using Pythagoras theorem

$PQ^2 + QR^2 = PR^2$

$5^2 + x^2 = (25 - x)^2$

$25 + x^2 = 625 + x^2 - 50x$

Solving $50x = 625 - 25 = 600$

or $x = \frac{600}{50} =12$ or $QR = 12$ cm and  $PR = 25 - 12 = 13$ cm

sin P = $\frac{opp}{hyp} = \frac{QR}{PR} = \frac{12}{13}$

cos P = $\frac{adj}{hyp} = \frac{PQ}{PR} = \frac{5}{13}$

tan P = $\frac{opp}{adj} = \frac{QR}{PQ} = \frac{12}{5}$


Updated on: 10-Oct-2022

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