Answer:
Step-by-step explanation:
Sum of interior angles of a polygon formula:

n represents the n-sided polygon

This is a fairly easy half-life problem
Each half-life reduces the radioactive material by one half.
So after 72 hours the radioactive material would have undergone 6 half-lives.
2^6 = 64.
So, there will be one sixty-fourth of the material left.
520 / 64 = 8.125 grams will remain.
radioactive decay is an exponential decay function.
Source:
http://www.1728.org/halflife.htm
Answer:
39ft by 34ft
Step-by-step explanation:
4 and 1/3 is equal (by doing 4*3+1)to 13/3 which is equal (by doing 13/3 *3/3)to 39/9 inches which according to the conversion is equal to 39ft
3 and 7/9 is equal (3*9+7)to 34/9 inches which when converted is 34ft