How do I solve this problem?

Which addition property is being illustrated below? (type commutative or associative) (6 + 7) + 1 = 6 + (7 + 1)

Suppose that 15 inches of wire cost 60 cents. at the same rate, how much (in cents) will 12 inches of wire cost

The average daily maximum temperature for laura’s hometown can be modeled by the function f(x)=4.5sin(πx/6)+11.8 , where f(x) is the temperature in °c and x is the month. x = 0 corresponds to january. what is the average daily maximum temperature in may? round to the nearest tenth of a degree if needed. use 3.14 for π .