To find the scale factor, we can compare corresponding sides of the triangles.
In the first triangle, SR = 5 and RT = 8.
In the second triangle, BC = 14, so the corresponding side must be 5 * (14/8) = 8.75.
Therefore, the scale factor is 8.75.
To find the length of AC, we use the scale factor.
In the first triangle, ST = 7.
Since the scale factor is 8.75, the corresponding side in the second triangle must be 7 * 8.75 = 61.25.
Therefore, the length of AC is 61.25.