Answer:
A. 11.33
Explanation:
In the blue rectangle, the ratio of the height to the width is 21/34.
In the red rectangle, the ratio of the height to the width is 7/w.
We are told the ratios are equal, so we set the ratios equal and solve for w.
7/w = 21/34
Cross multiply.
21w = 7 * 34
21w = 238
Divide both sides by 21.
w = 238/21
w = 11.333...
Answer: A. 11.33