Answer:
i got no clue
Step-by-step explanation:
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we know that
For a spherical planet of radius r, the volume V and the surface area SA is equal to

The
ratio of these two quantities may be written as

we know


therefore
the answer is

The percentage of the radioactive isotope left is 25.0000%.
<h3>What is the half life?</h3>
The half life of a radioactive isotope is the time that will elapse before only half of the number of original isotopes will remain.
Now;
We are told that;
Half life (t1/2) = 55 days
Time taken (t) = 115 days
Ratio of isotope remaining = N/No
Thus;
N/No = (1/2)^t/t1/2
N/No = (1/2)^115/55
N/No = (1/2)^2
N/No =1/4
Hence, the percentage = 1/4 * 100/1 = 25.0000%
Learn more about half life of an isotope:brainly.com/question/16387602
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Because There are 3 feet in 1 yard, so 3 feet and 1 yard are the same thing, hence a 1:1 ratio.