The missing side length in the second triangle is x = 2 + 1/2 = 5/2 inches.
In a dilation, the ratio of corresponding side lengths is always equal to the scale factor.
Therefore, we can set up the following proportion:
4/2 = (y+1)/x
Solving for x, we get:
x = (2 * (y+1)) / 4
x = y + 1/2
Now we can substitute the value of x back into the second triangle to find the missing side length:
y + 1 = 3
y = 2
Therefore, the missing side length in the second triangle is x = 2 + 1/2 = 5/2 inches.