Answer:
Step-by-step explanation:
JUst try your best
The area of the shaded region is
.
Solution:
Given radius = 4 cm
Diameter = 2 × 4 = 8 cm
Let us first find the area of the semi-circle.
Area of the semi-circle = 


Area of the semi-circle =
cm²
Angle in a semi-circle is always 90º.
∠C = 90°
So, ABC is a right angled triangle.
Using Pythagoras theorem, we can find base of the triangle.




cm
Base of the triangle ABC =
cm
Height of the triangle = 4 cm
Area of the triangle ABC = 

Area of the triangle ABC =
cm²
Area of the shaded region
= Area of the semi-circle – Area of the triangle ABC
= 
= 
Hence the area of the shaded region is
.
Answer:
The area is growing at a rate of 
Step-by-step explanation:
<em>Notice that this problem requires the use of implicit differentiation in related rates (some some calculus concepts to be understood), and not all middle school students cover such.</em>
We identify that the info given on the increasing rate of the circle's radius is 3
and we identify such as the following differential rate:

Our unknown is the rate at which the area (A) of the circle is growing under these circumstances,that is, we need to find
.
So we look into a formula for the area (A) of a circle in terms of its radius (r), so as to have a way of connecting both quantities (A and r):

We now apply the derivative operator with respect to time (
) to this equation, and use chain rule as we find the quadratic form of the radius:
![\frac{d}{dt} [A=\pi\,r^2]\\\frac{dA}{dt} =\pi\,*2*r*\frac{dr}{dt}](https://tex.z-dn.net/?f=%5Cfrac%7Bd%7D%7Bdt%7D%20%5BA%3D%5Cpi%5C%2Cr%5E2%5D%5C%5C%5Cfrac%7BdA%7D%7Bdt%7D%20%3D%5Cpi%5C%2C%2A2%2Ar%2A%5Cfrac%7Bdr%7D%7Bdt%7D)
Now we replace the known values of the rate at which the radius is growing (
), and also the value of the radius (r = 12 cm) at which we need to find he specific rate of change for the area :

which we can round to one decimal place as:

Answer:
No
Step-by-step explanation:
28*24=672. So, this is not even close to 800 and so isn’t reasonable.