Can scalene triangles ever be similar?

Yes, just keep the side lengths in the same ratio. This happens automatically if the three angles stay the same.

A scalene 3,4,5 trangle is similar to a 6,8,10 triangle.

No, scalene triangles cannot be similar. Similar triangles are triangles that have the same shape, but their sizes may vary. This means that their corresponding angles are equal, and the ratios of their corresponding sides are also equal.

Scalene triangles, on the other hand, have three unequal side lengths and three different angles. Because the side lengths and angles are not proportional, scalene triangles cannot be similar to each other.