In the accompanying diagram, ABC is isosceles, BC is extended to D. AB = AC. and M

m∠ACD = 130

Step-by-step explanation:

If ABC is an isosceles, AB = AC and m∠A = 80°, then m∠B and m∠C is equal to 50°.

This is because angles in a triangle adds up to 180°.

180° - 80° = 100°/2 = 50°

∴ m∠ACD = 130°, this is because the interior opposite angles in a triangle is supplementary to the opposite exterior angle:

50° + 80° = 130°

Or

Angles on a straight line adds up to 180°.

180° - 50° = 130°

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.