Answer:
y = 6.3
Explanation:
ΔLMN ~ ΔABC
The two triangles are similar which means the sides have the same proportions. To put it simply, one shape is just an enlargement of the other.
In this case, triangle ABC is an enlargement of triangle LMN so we can work out a scale factor.
To work out the scale factor, we can do 10 ÷ 7 = 1.4285714... To find y, all we have to do is divide 9 by the scale factor to get 6.3.
Hope this helps!