Question

If ∆ABC, if BC =AB and angle B=80°, than find angle A
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Answer 1

Answer:

MARK BRAINLIEST

Step-by-step explanation:

in  ∆ABC AB = BC,

then, ∠A =∠C = x let.....       ( acc. to  isosceles triangle rule)

∠A+∠B+∠C =180°

x + 80° + x = 180°

2x = 180°-80°

x = 100°/2

x = 50°

∠A = 50°

Answer 2

Answer:

Step-by-step explanation:

given :  BC = AB

∠B = 80°

To prove : ∠A

Proof : In ΔABC

BC = AB (GIVEN )

∠B = ∠A  ( angles opposite to equal sides are equal )

∠B = ∠A = 80 °

∴ ∠ A is 80°

             ( Hence proved )