Find the exact value of sin 30 degrees

Find the center and the radius of the circle with the equation: x^2-2x+y^2+4y+1=0?

What is the quotient of m^6/5 ÷ 5/m^2? assume m does not equal pl

In a small section of a stadium there are 40 spectators watching a game between the cook islands and fiji. they all support at least one of the two teams. 25 spectators support the cook islands and 16 of these support both teams. how many support only fiji?