Answer:
C
Step-by-step explanation:
I believe that the answer may be C, btw I am not sure, I think so. so if its not right, I am sorry but, I think that C is the correct answer.
Answer:
The angle of elevation to the top of the building is 63.61 degrees
Step-by-step explanation:
Here, we want to calculate angle of elevation to the top of the building.
For this, we need a triangle
Please check for this in the attachment.
From the diagram, we are to calculate the angle theta.
To do this, we use trigonometric identities.
Looking at what we have, we have the hypotenuse and the adjacent.
So the trigonometric identity to use is the cosine
Mathematically Cosine theta = adjacent/hypotenuse
Thus, Cos theta = 20/45
Cos theta = 0.444444444444444
Theta = Arc cos(0.444444444444444)
Theta = 63.61 degrees
Answer:
12:36
Step-by-step explanation:
<h3>Given</h3>
- a cone of height 0.4 m and diameter 0.3 m
- filling at the rate 0.004 m³/s
- fill height of 0.2 m at the time of interest
<h3>Find</h3>
- the rate of change of fill height at the time of interest
<h3>Solution</h3>
The cone is filled to half its depth at the time of interest, so the surface area of the filled portion will be (1/2)² times the surface area of the top of the cone. The filled portion has an area of
... A = (1/4)(π/4)d² = (π/16)(0.3 m)² = 0.09π/16 m²
This area multiplied by the rate of change of fill height (dh/dt) will give the rate of change of volume.
... (0.09π/16 m²)×dh/dt = dV/dt = 0.004 m³/s
Dividing by the coefficient of dh/dt, we get
... dh/dt = 0.004·16/(0.09π) m/s
... dh/dt = 32/(45π) m/s ≈ 0.22635 m/s
_____
You can also write an equation for the filled volume in terms of the filled height, then differentiate and solve for dh/dt. When you do, you find the relation between rates of change of height and area are as described above. We have taken a "shortcut" based on the knowledge gained from solving it this way. (No arithmetic operations are saved. We only avoid the process of taking the derivative.)
Note that the cone dimensions mean the radius is 3/8 of the height.
V = (1/3)πr²h = (1/3)π(3/8·h)²·h = 3π/64·h³
dV/dt = 9π/64·h²·dh/dt
.004 = 9π/64·0.2²·dh/dt . . . substitute the given values
dh/dt = .004·64/(.04·9·π) = 32/(45π)
