Answer:

Explanation:
We know that the perimeter of the triangle is 60 feet, that is, the sum of all three sides is 60 feet.
Now, if each triangle is multiply by 10, that means the perimeter would be increased ten time also.
Therefore, the perimeter would be 600 feet.
If you wanna use formulas, we have


Where
represents the ares and
represents the perimeter.
The area of a triangle is

Where
and
represent the legs of the right triangle.

Where
represents the hypothenuse of the right triangle.
After increasing sides by a scale factor of 10, the perimeter would be

Which shows the increasing scaling factor, then we extract this common scale factor.

Which means that the perimeter increased is just the old perimeter multiplied by 10, as follows
