Answer:
1.
by using Pythagoras theorem
h²=p²+b²
h²=12²+40²
h=√1744
AB=42
2.
x+48°+90°=180°{sum of interior angle of triangle}
x=180°-138°
x=42°
Okay so...
There are 21 groups of 3.
21 x 3 = 63.
63 people are in the room.
Ok
Lets start:

is 36
then you add 8 which would be 44.
then do 7 times 2 which is 14, then add 11, which is 25.

is 44 divided by 25, which would be 1.76
Ming needs to play for 15 hours to get 500 points. They gave him 200 for signing up, so 500-200=300 more points needed. 300 divided by 20= 15 more hours.