Question

if one angle of a triangle is equal to the sum of the other two show that the triangle is righted triangle

Answer 1

sum of all angles 180
let the angles be x, x and 2x
thus, x+x+2x=180
4x=180
x=45
therefore one angle is 45 and double of it I.e. 2x is 90
thus one angle of a triangle is 90
hence it is a right angled triangle
I hope my answer is right and it helped you