Answer:
4 yd
Explanation:
The missing length is the question mark on the top side.
Look at the bottom side. Its length is 10 yd.
Now look at the next horizontal side up from the bottom. Its length is 6 yd.
The missing length is the difference between 10 yd and 6 yd.
10 yd - 6 yd = 4 yd