(D) A right triangle
Explanation:
Let the angles of △ABC be ∠A, ∠B and ∠C
Given that ∠A= ∠B+∠C …(eq1)
But, in any △ABC,
Using angle sum property, we have,
∠A+∠B+∠C=180o …(eq2)
From equations (eq1) and (eq2), we get
∠A+∠A=180o
⇒2∠A=180o
⇒∠A=180o/2 = 90o
⇒∠A = 90o
Hence, we get that the triangle is a right triangle
Therefore, option (D) is the correct answer.