Can somebody pls help and explain it rlly good I’ve been stuck on this for hrs pls help

In a class, there are 12 girls. if the ratio of boys to girls is 5: 4 how many boys are there in the class

Which statement explains how you could use coordinate geometry to prove the opposite sides of a quadrilateral are congruent? a. use the slope formula to prove the slopes of the opposite sides are the same. b. use the slope formula to prove the slopes of the opposite sides are opposite reciprocals. c. use the distance formula to prove the lengths of the opposite sides are the same. d. use the distance formula to prove the midpoints of the opposite sides are the same.

What else equals 42 and 30 for multiply