Find the length indicated.
?
5
5) G
17
A) 12
B) 36
C) 21

your answer would be A.)12

Step-by-step explanation: You needed to find out what number you can put for it to add up to the number on the bottom line, 17. So you would add (12+5=17) , And you would get the same number as the number  on the bottom line.

~hope this explanation has helped~