Help with Trig please.
Similar polygons: ratios of perimeters and areas.

The Δ are similar. The sides of the first Δ are 4,5,6. The largest side of the second Δ is 24. Find the perimeter of the second Δ.

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)

If the value of cos330°is√3/2 then find cos 165°.