Answer:
Such triangles do not exist.
Explanation:
There is some mistake in your question.
We know:
In any triangle with sides a, b and c:
a + b > c
a + c > b
b + c > a
In your question the triangle ABC has:
a = 5, b = 10, c = 15
then
5 + 10 = 15 not > 15.
a + b = c not > c.
In my opinion, the question makes no mathematical sense.
Nevertheless, the moderator asked me to correct my answer.
If two triangles are similar, then corresponding sides are in proportion.