-7 -(-7) because it will equal zero and the other one will be -14
Answer:
28π cm²
Step-by-step explanation:
The surface of a cylinder is given by the formula:
where r is the radius of the base, and h is the height.
Using the image, we can find that the radius of the cylinder would be 2 cm, and the height would be 5 cm.
Now, to find the surface area of the cylinder, we would have to plug in 2 for r (the radius of the base) and 5 for h (the height of the cylinder) into the formula for the surface area of a cylinder.
Now we plug in 2 for r and 5 for h for the equation for the surface area of a cylinder:
2π(2)(5) + 2π(2)² = 20π + 2π(4) = 20π + 8π = 28π
Remember, the radius and the height are given to us in cm, and w are solving for surface area, so the answer should be in cm² (square centimeters).
The surface area of the cylinder would be 28π cm².
28π cm² would be an exact answer. For the approximate answer, plug in 3.14 (most math classes use 3.14 to approximate π) for π.
I hope you find this helpful. :)
Answer:

Step-by-step explanation:
From similar triangles, see diagram in attachment

We solve for
to obtain,

The formula for calculating the volume of a cone is

We substitute the value of
to obtain,

This implies that,

We now differentiate both sides with respect to
to get,

We were given that water is drained out of the tank at a rate of 
This implies that
.
Since we want to determine the rate at which the depth of the water is changing at the instance when the water in the tank is 8cm deep, it means
.
We substitute this values to obtain,




Answer:
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Step-by-step explanation: