Can someone help me with this please ?

The corner is 90 degrees so I believe you add them so 60+90+30 is 180!!!

The answer will be 180

Let us find a function of the cost with respect to the number of months.

y=mx+b, where y=cost and x=months.

First find the slope, "m", (y2-y1)/(x2-x1)

m=(30.5-15.25)/(2-1)

m=15.25 so far we now have:

y=15.25x+b, we can solve for b using any point, I'll use (1, 15.25)

15.25=15.25(1)+b

15.25=15.25+b

0=b, so the cost function is:

c(m)=15.25m

c, cost,  is the dependent variable because it depends on the independent variable m, months.