<span>As the age of the U-235 sample is 2.631 billion years, and the half-life of U-235 is 713 million years, the sample has undergone 2.361 X 1,000,000,000 / 713 X 1,000,000 = 3.69 half lives. In each half-life the sample reduces to half its original weight according to the radioactive Half-Life Formula:
ln (Nt /N0) = -kt, where N0 = mass of the original weight of radioactive material, Nt = mass of radioactive material at time t, k = decay constant and t = time interval . We have to put Nt/N0 = 1/2 for time interval = half-life.</span>
The square that has a perimeter of 84 ft has the longer side.
It is 9 because I think It is equaltion to 9
<span><u>PLAN</u>
</span>(2,4) and (2,-3)
<span><u>SOLVE</u>
</span>. 2
. |4|= 4 |-3|=<span> 3
</span>. Distance from (2,4) to the x-axis= <span>6
</span>. Distance from (2,-3) to the x-axis=<span> -1
. 6 + (-1) = 5 blocks
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