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Question
If one angle of a triangle is equal to the sum of the other two, show that the triangle is a
right triangle.
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Solution
If one angle of a triangle is equal to the sum of other two
i.e, `∠ B=∠ A+∠C`
Now, in ΔABC
(Sum of all aangles of triangle `180^@`)
`∠ A+∠B+∠ C=180^@`
`∠ B+∠ B=180^@` [∵ ∠ B=∠ A+∠ C]
`2∠ B=180^@`
`∠ B=180^@/2`
`∠ B=90^@`
∴ABC is a right angled a triangle
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