Mathematics
In △ABC, BC = AB and ∠B = 80°. Then ∠A is equal to
80°
40°
50°
100°
Triangles
ICSE
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Answer
Since in △ABC, BC = AB.
∴ ∠A = ∠C. (As angles opposite to equal sides in isosceles triangle are equal.)
Let ∠A = ∠C = x.
Sum of angles of triangle = 180°.
∠A + ∠B + ∠C = 180°
x + 80° + x = 180°
2x = 100°
x = 50°
∠A = 50°.
Hence, Option 3 is the correct option.
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