Can you determine the third angle measure in a triangle, if you know the other two angles?

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

With #! i’ve tried to figure it out but i can’t.

Match each equation with the operation you can use to solve for the variable. 1 subtract 10 2 divide by 10 3add 18 4add 10 5 subtact 18 6multiply by 5. 7multiply by 10. a 5 = 10p b p + 10 = 18 c p + 18 = 5 d 5p = 10