Question

if one angle of a triangle is equal to the sum of the other two so that the triangle is right angled

Answer 1

I think this is true because in a right angle triangle one angle is 90 degree and according to the angle sum property The Other angles should also be equal to 90 degree so if one angle of a triangle is equal to the sum of the other two I think it is a right triangle but you should be sure before making any decision

Answer 2

yes...
let one angle be X other be y
the third will be X+y


as we know... sum of internal angles = 180

X+y+X+y=180
X+y=90

hence it's a right angled ∆