Help me answer this question

7m

Step-by-step explanation:

1. find ratio of small to large triangle (6:18 = 1:3 / 8:24 = 1:3)

2. find blank side of smaller triangle (if ratio is 1:3 then take the large triangle side that matches the smaller unknown side and divide by 3 to size down the line to find unknown side)

Answer = 7m