A toy pyramid has the dimensions shown below. The base of the pyramid is an equilateral triangle. What is the surface area of this pyramid? 48 cm 2
129 cm 2
102 cm 2
81 cm 2

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?