Let First angle = 3x

Second angle = 4x

Third angle = 5x

and fourth angle = 8x

We know 3x + 4x+ 5x + 8x = 360 degree

=> 20x = 360 degree

x = 18 degree

Measure of smallest angle

= 3x =\( \Large 3\times 18 \  degree \)=54 degree