Angle and side relationship question (See picture)

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

In δabc, if the length of side b is 3 centimeters and the measures of ∠b and ∠c are 45° and 60°, respectively, what is the length of side c to two decimal places?

Place the following steps in order to complete the square and solve the quadratic equation,