Find the altitude of an equilateral triangle if each side of the triangle has a length of 20 m.

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

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.

Can someone check if i did this right since i really want to make sure it’s correct. if you do you so much