9514 1404 393
Answer:
111 1/9 pounds
Step-by-step explanation:
The given relationship is ...
delivered = ground × (1 -10%)
Then ...
ground = delivered/0.90 = 100 lb/0.90 = 111 1/9 lb
It is necessary to grind 111 1/9 pounds of grain to have exactly 100 lb after a 10% payment.
4/3 because (check the picture)
There will be 18 exterior angles, each of 360/18 = 20 deg. So each interior angle, which is supplementary to the exterior angle will be 180–20 - 160 deg. The sum of the 18 interior angles = 18*160 = 2880 deg.