300 ft jdndjdjdjdnnsbshshdbdbbdbdhd
Answer:
Percentage of (226Ra) after 900 years is 68%
Step-by-step explanation:
Let P(t) be the amount of (226Ra) present at any time t
Half life of (226 Ra) = 1599 years
If P₀ is initial amount of (226 Ra) then after 1599 years
P(1599)=P₀/2
Decay i amount of radioactive substance is related to time t as

To find value of k

Percentage of radioactive element is:
Amount after 900 years
Given:
The three vertices of the parallelogram are (-3,9), (0,-3), (6,-6).
To find:
The fourth vertex of the parallelogram.
Solution:
Consider the three vertices of the parallelogram are A(-3,9), B(0,-3), C(6,-6).
Let D(a,b) be the fourth vertex.
Midpoint formula:

We know that the diagonals of a parallelogram bisect each other. So, the midpoints of both diagonals are same.
Midpoint of AC = Midpoint BD


On comparing both sides, we get


And,




Therefore, the fourth vertex of the parallelogram is (3,6).
The answer is the first choice.
P(both even) = (4P1)(3P1) / 9P2