Answer:
The rate of change of the height is 0.021 meters per minute
Step-by-step explanation:
From the formula

Differentiate the equation with respect to time t, such that


To differentiate the product,
Let r² = u, so that

Then, using product rule
![\frac{dV}{dt} = \frac{1}{3}\pi [u\frac{dh}{dt} + h\frac{du}{dt}]](https://tex.z-dn.net/?f=%5Cfrac%7BdV%7D%7Bdt%7D%20%3D%20%5Cfrac%7B1%7D%7B3%7D%5Cpi%20%5Bu%5Cfrac%7Bdh%7D%7Bdt%7D%20%2B%20h%5Cfrac%7Bdu%7D%7Bdt%7D%5D)
Since 
Then, 
Using the Chain's rule

∴ ![\frac{dV}{dt} = \frac{1}{3}\pi [u\frac{dh}{dt} + h(\frac{du}{dr} \times \frac{dr}{dt})]](https://tex.z-dn.net/?f=%5Cfrac%7BdV%7D%7Bdt%7D%20%3D%20%5Cfrac%7B1%7D%7B3%7D%5Cpi%20%5Bu%5Cfrac%7Bdh%7D%7Bdt%7D%20%2B%20h%28%5Cfrac%7Bdu%7D%7Bdr%7D%20%5Ctimes%20%5Cfrac%7Bdr%7D%7Bdt%7D%29%5D)
Then,
![\frac{dV}{dt} = \frac{1}{3}\pi [r^{2} \frac{dh}{dt} + h(2r) \frac{dr}{dt}]](https://tex.z-dn.net/?f=%5Cfrac%7BdV%7D%7Bdt%7D%20%3D%20%5Cfrac%7B1%7D%7B3%7D%5Cpi%20%5Br%5E%7B2%7D%20%5Cfrac%7Bdh%7D%7Bdt%7D%20%2B%20h%282r%29%20%5Cfrac%7Bdr%7D%7Bdt%7D%5D)
Now,
From the question


At the instant when 
and 
We will determine the value of h, using





Now, Putting the parameters into the equation
![\frac{dV}{dt} = \frac{1}{3}\pi [r^{2} \frac{dh}{dt} + h(2r) \frac{dr}{dt}]](https://tex.z-dn.net/?f=%5Cfrac%7BdV%7D%7Bdt%7D%20%3D%20%5Cfrac%7B1%7D%7B3%7D%5Cpi%20%5Br%5E%7B2%7D%20%5Cfrac%7Bdh%7D%7Bdt%7D%20%2B%20h%282r%29%20%5Cfrac%7Bdr%7D%7Bdt%7D%5D)
![236 = \frac{1}{3}\pi [(99)^{2} \frac{dh}{dt} + (\frac{20}{363\pi }) (2(99)) (7)]](https://tex.z-dn.net/?f=236%20%3D%20%5Cfrac%7B1%7D%7B3%7D%5Cpi%20%5B%2899%29%5E%7B2%7D%20%5Cfrac%7Bdh%7D%7Bdt%7D%20%2B%20%28%5Cfrac%7B20%7D%7B363%5Cpi%20%7D%29%20%282%2899%29%29%20%287%29%5D)
![236 \times 3 = \pi [9801 \frac{dh}{dt} + (\frac{20}{363\pi }) 1386]](https://tex.z-dn.net/?f=236%20%5Ctimes%203%20%3D%20%5Cpi%20%5B9801%20%5Cfrac%7Bdh%7D%7Bdt%7D%20%2B%20%28%5Cfrac%7B20%7D%7B363%5Cpi%20%7D%29%201386%5D)






Hence, the rate of change of the height is 0.021 meters per minute.
Answer:
77cm
Step-by-step explanation:
Area of a rectangle=L×B
So
7×11=77cm
Option 3:
m∠ABC = 66°
Solution:
Given
and ABH is a transversal line.
m∠FAB = 48° and m∠ECB = 18°
m∠ECB = m∠HCB = 18°
<u>Property of parallel lines:
</u>
<em>If two parallel lines cut by a transversal, then the alternate interior angles are equal.</em>
m∠FAB = m∠BHC
48° = m∠BHC
m∠BHC = 48°
<u>Exterior angle of a triangle theorem:
</u>
<em>An exterior angle of a triangle is equal to the sum of the opposite interior angles.</em>
m∠ABC = m∠BHC + m∠HCB
m∠ABC = 48° + 18°
m∠ABC = 66°
Option 3 is the correct answer.
1) Work out what 1/5 of 12 is
To do this, we divide 12 by 5
12/5 = 2.4
2) Multiply 2.4 by 15
2.4 x 15 = 36
<em>If you don't like decimals, you can also do it this way...
</em>
This can be rewritten as 15 x 1/5 x 12
Multiplications alone can be performed in any order
1) Work out what 1/5 of 15 is
1/5 of 15
15/5 = 3
2) 3 multiplied by 12
3 x 12 = 36
If y = √(2x + 1), then differentiating both sides implicitly with respect to t gives
dy/dt = 1/2 • 1/√(2x + 1) • 2 • dx/dt = 1/√(2x + 1) • dx/dt
(a) If dx/dt = 9 and x = 4, then
dy/dt = 1/√(2•4 + 1) • 9
dy/dt = 1/√(8 + 1) • 9
dy/dt = 1/√9 • 9
dy/dt = 9/3
dy/dt = 3
(b) If dy/dt = 3 and x = 40, then
3 = 1/√(2•40 + 1) • dx/dt
3 = 1/√(80 + 1) • dx/dt
3 = 1/√81 • dx/dt
3 = 1/9 • dx/dt
dx/dt = 27