The new height is 20 in.
Explanation:
Let the width and height of the original triangle be w1 and h1
w1 = 5 in
h1 = 4 in
Let the width and height of the enlarged triangle be w2 and h2
w2 = 25 in
h2 = ?
(Since the triangles are similar, we can use the ratio of the given sides)
h2 / h1 = w2 / w1
h2 / 4 = 25 / 5
h2 / 4 = 5
h2 = 5 x 4
h2 = 20 in