Which angles are vertical angles in the figure shown? Select two answers.
A. ∠1 and ∠2
B. ∠2 and ∠3
C. ∠5 and ∠8
D. ∠4 and ∠5
E. ∠7 and ∠8

Aparticular telephone number is used to receive both voice calls and fax messages. suppose that 25% of the incoming calls involve fax messages, and consider a sample of 25 incoming calls. (a) what is the expected number of calls among the 25 that involve a fax message?