Answer
smallest angle = 30
medium angle = 60
largest angle = 90
This is a 30-60-90 right triangle
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Work Shown
x = some positive real number
1x = smallest angle
2x = medium angle
3x = largest angle
The ratio 1x:2x:3x reduces to 1:2:3 when you divide all parts by x, which shows the angles are in the proper ratio.
For any triangle, the three angles always add to 180.
1x+2x+3x = 180
6x = 180
x = 180/6
x = 30
smallest angle = 1x = 1*30 = 30
medium angle = 2x = 2*30 = 60
largest angle = 3x = 3*30 = 90
This is a 30-60-90 right triangle.