CBSE Class 7 Answered

Let the measure of angles of the triangle be a, b, and c.

Then by angle sum property in triangles we have

a + b + c = 180 ... (1)

Also, given that

c = a + b ...(2)

Hence, 

Sub (2) in (1), we get

c + c = 180

∴ 2c = 180

∴ c = 90

Hence, the triangle is right-angled.