30. Find the volume of the figure below. 21 km 15 km 19 km 9 km
1 answer:
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Answer:
Step-by-step explanation:
The perimeter of a rectangle can be calcualated with this formula:
Where "l" is the lenght and "h" is the height.
The area of a rectangle can be found with this formula:
Where "l" is the lenght and "h" is the height.
In this case we know that:
Therfore, we can susbsitute them into and solve for "h" in order to find its value:
Find two number whose sum is 3 and whose product is -40. These are -5 and 8. Then, factorizing, we get:
The positive value is the height. Then:
Since the length is 3 centimeters greater than its height, we get that this is: Then:
Substituting values into , we get that the perimeter is:
Answer:
Per hour decay of the isotope is 0.96%.
Step-by-step explanation:
Amount of radioactive element remaining after t hours is represented by
where a = initial amount
t = duration of decay (in hours)
Amount remaining after 1 hour will be,
y = 0.9904a
So amount of decay in one hour = a - 0.9904a
= 0.0096a gms
Percentage decay every hour =
=
= 0.958 %
≈ 0.96 %
Therefore, per hour decay of the radioactive isotope is 0.96%.