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%
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This graph shows a proportional relationship. What is the constant of proportionality? Enter your answer as a ratio in simplified form in the box.
Here, we are required to find the area of the paper board given after the semicircle is cut out of it
Area of the paper board thatremains is 423 in²
Length = 29 in
Width = 20 in
Area of a rectangle = length × width
= 29 in × 20 in
= 580 in²
Area of a semi circle = πr²/2
π = 3.14
r = diameter / 2 = 20 in / 2 = 10 in
Area of a semi circle = πr²/2
= 3.14 × (10 in)² / 2
= 3.14 × 100 in² / 2
= 314 in²/2
= 157 in²
The semicircle is cut out of the rectangle
Find the area of the paper board that remains after the semicircle is cut out of it by subtracting the area of a semi circle from the area of a rectangle
Area of the paper board that remains = Area of a rectangle - Area of a semi circle
= 580 in² - 157 in²
= 423 in²
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