Answer:
I think SSS ,.............
25
The triangle given by 9, unknown, and 15 and the triangle given by 15, unknown, and x are similar triangles and therefore 9:15 = 15:x
X is 25 in this case
Answer:

Step-by-step explanation:
See pic.
Answer:
15%
Step-by-step explanation:
100-85=15
100%= the total cost of the book
85%= price she bought it for
15%= the percentage the book was reduced by