Question 855643
Perimeter being a length, or a distance, means the side lengths are also in the same 2:4 proportion, actually 1:2 ratio, because 1:2 is reduced.


Small triangle:
perimeter x+y+z, and if assumed z is a hypotenuse and the triangles are Right, then
area is {{{(1/2)xy}}}.


Large triangle:
perimeter would be 2x+2y+2z=2(x+y+z).  As similar to the small one,
area is {{{(1/2)(2x)(2y)=2xy}}}.


Look at now the ratio of their areas.  (1/2):2, or {{{(1/2)/2=1/4}}}, small to large;  This means, if cut the large AND small together into 5 equal parts, the small triangle is 1 of those parts, and the large triangle is 4 of those parts; together making the 5 equal parts.


Cut {{{100cm^3}}} into 5 equal parts:  {{{20cm^3}}} in each part.  This means small triangle is {{{20cm^3}}} and large triangle is {{{80cm^3}}}.