The Triangles are similar.
What is the value of x?

Answer:
12
Step-by-step explanation:
Sides are in the ratio 28:7,
Which is also 4:1
The length of sides of the bigger triangle are 4 times the length of the smaller one.
6x+28 = 4(25)
6x+28 = 100
6x = 72
x = 12