Answer:
? = 2
Explanation:
The order of letters in the similarity statement tells you the corresponding sides. Corresponding sides have the same ratios:
BC/BD = BR/BS
7/14 = ?/4 . . . . . . . . fill in the values from the diagram
4(1/2) = ? = 2 . . . . . simplify the fraction 7/14, multiply by 4