Answer:
12
Step-by-step explanation:
This triangle is a 3-4-5 Pythagorean Triple. 9 is 3*3, 15 is 5*3, so b is 4*3, which is 12. Alternatively, you could use the Pythagorean Theorem's converse, sqrt(15^2-9^2), and get 12.
The answer is 3 over 4
i believe its a square :)