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
