8 find the missing length

C) 15m

Step-by-step explanation:

Since this is a right triangle (we know this since the box in the top left of the image shows that angle is 90°) We can use the pythagorean theorem.

formula for the pythagorean theorem = a² + b² = c²

The easiest way to think about this is to just know that the long side (our missing side in this case) is "c."

So, we plug our numbers in: (it doesn't matter which legs of the triangle you use for "a" or "b")

9² + 12² = x²

9² = 81

12² = 144

81 + 144 = 225

now we know the missing side (squared) is 225. All we need to do is just find the square root () of 225.

= 15

15 is your answer.

a) one student is chosen from classroom a, then a student is chosen from classroom b.  

step-by-step explanation:

independent events are ones in which the probability of one event does not affect the probability of the second event.

one student is chosen from classroom a; this does not affect the chances of choosing a student from classroom b.   this makes these independent events.

when one card is chosen from a standard deck and then set aside before a second card is chosen, the probability of the second card being chosen changes.   this makes them dependent events.

when one student is chosen from classroom a and then a second student is chosen from classroom a, the probability of choosing the second student changes.   this makes them dependent events.

when a letter is chosen from the alphabet and then a second letter is chosen, the probability of choosing the second letter changes.   this makes them dependent events.