NCERT - Mathematics

Book: NCERT - Mathematics

Chapter: 8. Introduction to Trigonometry

Subject: Maths - Class 10th

Q. No. 10 of Exercise 8.1

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10

In Δ PQR, right-angled at Q, PR + QR = 25 cm and PQ = 5 cm. Determine the values of Sin P, Cos P and tan P

Given that, PR + QR = 25

PQ = 5


Let PR be x


Therefore,


QR = 25 - x



Applying Pythagoras theorem in ΔPQR, we obtain


PR2 = PQ2 + QR2


x2 = (5)2 + (25 - x)2


x2 = 25 + 625 + x2 - 50x


50x = 650


x = 13


Therefore,


PR = 13 cm


QR = (25 - 13) cm = 12 cm


Sin P =


Cos P =


Tan P =


14

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