He need 7 blankets because if you take away 3 7 times from the 21 u get 0
The equilateral triangle is the pattern block used to cover one-sixth of a hexagon.
To find the probability of the ball landing outside the free throw box but on the court you find the total area of the court and subtract the area of the free throw box.
Then create a ratio with the part of the court not with the free throw box and the total court area. Divide these.
Total area = 25.6 x 15.2 =389.12 square meters
Free throw space = 5.8 x 3.7=
21.46 square meters
389.12-21.46=367.66 square meters
367.66/389.12=0.95
There is a 0.95 probability that it will land on the court outside of the free throw box.