Answer:
c.
Explanation:
The original triangle has two sides with length 4x each, and the hypotenuse has length 3y.
After the enlargement, each of the sides with length 4x becomes 3y × 4x = 12xy, and the hypotenuse becomes 3y × 3y = 9y^2.
Therefore, the perimeter of the enlarged triangle is the sum of the lengths of its three sides:
12xy + 12xy + 9y^2 = 24xy + 9y^2 = 9y^2 + 24xy
So the answer is (C) 9y^2 + 24xy.