Question

त्रिभुज ABC में, यदि कोण B = 60 °, b = 11 सेमी और c = 8.7
सेमी है तो कोण A का मान होगा
IT विभाल के लिए माडन नियम टोना​

Answer 1

Answer:

Measure of angle A would be 76.77° ( approx )

Step-by-step explanation:

Given,

In triangle ABC,

m∠B = 60°, b = AC = 11 cm, c = AB = 8.7 cm,

∵ By the law of sine,

$\frac{\sin B}{b}=\frac{\sin C}{c}$

$\implies \frac{\sin 60^{\circ}}{11}=\frac{\sin C}{8.7}$

$\implies \sin C = \frac{8.7\sin 60^{\circ}}{11}$

$\implies m\angle C \approx 43.23^{\circ}$

∵ The sum of all interior angles of a triangle is 180°,

m∠A + m∠B + m∠C = 180°,

⇒ m∠A + 60° + 43.23° = 180°

⇒ m∠A + 103.23° = 180°

⇒ m∠A =  180° - 103.23° = 76.77°