create a similar but bigger polygon

If I have a polygon say the triangle A=(1,0), B= (2,1),C = (3,0)}formed from x=[1 2 3], y=[0 1 0] using respectively the first, second and third elements of x and y vectors, how can I create a similar polygon triangle at a fixed distance from the points on the triangle?

Answer 1

[Steven Lord]

If you're using release R2017b or later, use polybuffer on a polyshape.

Answer 2

[Matt J]

For example,

triangle=polyshape(x,y);

[cx,cy]=centroid(triangle);

biggertriangle=scale(triangle,2, [cx,cy])