What is the number of degrees of freedom that should be used for finding the critical value

There are 20 children in the cast of a class play and 8 of the children are boys of the boys 4 have a speaking part in the play and of the girls 8 do not have a speaking part in the play if a child from the cast of the place chosen at random what is the probability that the child has a speaking part

The angle of a triangle are given as 6x,(x-3), and (3x+7). find x then find the measures of the angles

What are the equivalent ratios for 24/2= /3= /5.5=108/ = /15