<image>Some students in the math interest group of the seventh grade at a certain school conducted a survey among several parents on their views regarding the phenomenon of "middle school students bringing mobile phones to school." They compiled the statistics and produced the following bar and pie charts. Based on the information in the charts, answer the following questions:
(1) How many parents participated in this survey?
(2) How many parents showed an "indifferent" attitude?
(3) In the pie chart, find the central angle corresponding to the "disapprove" portion.
