Answer :
We know that sum of angles in the triangle its 180.
To get the answer we can prepare equation
x+x+4x=180
6x=180 /:6
x=30 - first and second angles
4x=30*4=120 - third angle
To get the answer we can prepare equation
x+x+4x=180
6x=180 /:6
x=30 - first and second angles
4x=30*4=120 - third angle