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Question
From given figure, In ∆ABC, AB ⊥ BC, AB = BC then m∠A = ?
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Solution
AB = BC ...[Given]
∴ ∠A = ∠C ...[Isosceles triangle theorem]
Let ∠A = ∠C = x
In ∆ABC,
∠A + ∠B + ∠C = 180° ...[Sum of the measures of the angles of a triangle is 180°]
∴ x + 90° + x = 180°
∴ 2x = 180° – 90°
∴ 2x = 90°
∴ x = `(90°)/2`
∴ x = 45°
∴ m∠A = 45°
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