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%.
Let
x---------> the length of the rectangle
y--------> the width of the rectangle
we know that
A=84 ft²
[area of rectangle]=x*y-----> 84=x*y-----> equation 1
x=y-5------> equation 2
substitute 2 in 1
84=[y-5]*y-----> 84=y²-5y---------> y²-5y-84=0
using a graph tool-----> to resolve the second order equation
see the attached figure
the solution is
y=12
x=y-5-----> x=12-5-----> x=7
the answer isthe length of the rectangle is 7 ftthe width of the rectangle is 12 ft
Just do b*h/2 for all the triangles.
In every triangle,if one of those three angles has his measure more than 90°,then the triangle is optuse.
If all three angles are 60°,it means the triangle equiangular.
If one of those three angles is equal to 90°,the triangle is right.
If all the angles of the triangle have their measure less than 90°,the triangle is acute.
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Your triangle has an angle bigger than 90°,it means the triangle is optuse.
