METHOD 1
f(3) = 20
f(4) = 30
f(5) = 42
f(6) = 56
rate of change
f(4)-f(3)=10
f(5)-f(4)=12
f(6)-f(5)=14
then the average of change is 10+12+14 /3 = 12
METHOD 2 --- faster
rate of change = f(6)-f(3) / 6-3
= (36+18+2)-(9+9+2) / 3
= 36/3 = 12
6x = 16 +14
6x = 30
30 / 6 =5
x= 5
it depends on what type of triangle is it a right triangle?
The radii of the frustrum bases is 12
Step-by-step explanation:
In the figure attached below, ABC represents the cone cross-section while the BCDE represents frustum cross-section
As given in the figure radius and height of the cone are 9 and 12 respectively
Similarly, the height of the frustum is 4
Hence the height of the complete cone= 4+12= 16 (height of frustum+ height of cone)
We can see that ΔABC is similar to ΔADE
Using the similarity theorem
AC/AE=BC/DE
Substituting the values
12/16=9/DE
∴ DE= 16*9/12= 12
Hence the radii of the frustum is 12
