A184B210C241D425Answer: A. 184 Read Explanation: So the intended rule:Bottom=Left2−Right2\boxed{\text{Bottom} = \text{Left}^2 - \text{Right}^2}Bottom=Left2−Right2For the third figure:252−212=625−441=18425^2 - 21^2 = 625 - 441 = 184252−212=625−441=184Thus the answer is:184\boxed{184}184 Read more in App