Answer:
56
Step-by-step explanation:
Missing length = x + 21
Based on the Three Parallel Lines Theorem, we have:
x/21 = 20/12
Cross multiply
x*12 = 20*21
12x = 420
12x/12 = 420/12
x = 35
✅Missing length = x + 21
Plug in the value of x
= 35 + 21
= 56
