If the angles of a triangle have a ratio of 1 to 2 to 6 then what is the measure largest angle?

The angles in a triangle always add up to 180o. If you have a ratio of 1 units to 2 units to 6 units then you have a total of 9 units in your triangle.

Hence 180/9 = 20. So 1 unit is equal to 20o. The largest angle is 6 units, so 6 x 20o = 120o