Does 21, 10, and 9 be the measures of the sides of a triangle

no

Step-by-step explanation:

The sum of the lengths of any two sides of a triangle is greater than the length of the third side.

9+10 > 21

19 >21

This is not true so it cannot make a triangle

1,150 give brainliest

step-by-step explanation

2r= 2300

r =1150

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.