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In ΔABC right angled at B, AB = 24 cm, BC = 7 m. Determine: sin A, cos A

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Question

In ΔABC right angled at B, AB = 24 cm, BC = 7 m. Determine:

sin A, cos A

Sum
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Solution

ΔABC is right angled at B

AB = 24 cm, BC = 7 cm

Let ‘x’ be the hypotenuse,

By applying Pythagoras

AC2 = AB2 + BC2

x2 = 242 + 72

x2 = 576 + 49

x2 = 625

x = 25

For Sin A, Cos A

At ∠A, opposite side = 7

adjacent side = 24

hypotenuse = 25

sin A = `"opposite side"/"hypotenuse" =("BC")/("AC") =  7/25`

cos A = `"adjacent side"/"hypotenuse" = ("AB")/("AC") = 24/25`

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Chapter 8: Introduction to Trigonometry - EXERCISE 8.1 [Page 121]

APPEARS IN

NCERT Mathematics [English] Class 10
Chapter 8 Introduction to Trigonometry
EXERCISE 8.1 | Q 1.(i) | Page 121
R.D. Sharma Mathematics [English] Class 10
Chapter 10 Trigonometric Ratios
Exercise 10.1 | Q 2 .1 | Page 23

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