914,545 rounded to the nearest ten is 914,550.
You take 4/15 and make the denominator 315
4/15 = ?/315
15 x 21 = 315
4 x 21 = 84
4/15 = 84/315
so 84 of 315 members are male
315 - 84
= 231
231 are female
Answer: Choice B) 
We have some value m and we're squaring it to get 
To undo this and isolate m, we apply the square root to both sides

There are two solutions here. This is similar to how there are two solutions in something like
(those two solutions being x = 5 and x = -5). Squaring any negative number leads to a positive result because
negative times negative = positive.
2.5 x 2 = 5
Answer = 5 miles/hour