Question

In∆ ABC, bc = ab and lb = 80 ,then angle A is equal to
a)80°
b)50°
c)50°
d)100°​

Answer 1

Answer:

Given : angle b = 80 degree, bc = ab

R.T.F : angle a = ?

Finding : angle a = angle c

let, angle a = angle c = x

sum of three anglecof a triangle is = 180 degree

So,

a + b + c = 180 degree

=> x + x + 80 = 180

=> 2x = 180 - 80

=> 2x = 100 degree

=> x = 100/2

=> x = 50 degree

angle a = angle c = 50 degree

therefore, angle A = 50 degree

Ans. b) 50 degree.

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