Question : The fourth proportional to 16, 26, and 32 is:

Option 1: 16

Option 2: 52

Option 3: 54

Option 4: 24

Question : What is the ratio of the mean proportional between 1.6 and 3.6 and the third proportional of 5 and 8?

Option 1: 2 : 15

Option 2: 5 : 16

Option 3: 3 : 16

Option 4: 4 : 15

Question : The third proportional of $a$ and $\frac{b^4}{4a}$ is:

Option 1: $\frac{b^8}{16 a^2}$

Option 2: $\frac{b^8}{8 a^2}$

Option 3: $\frac{b^8}{8 a^3}$

Option 4: $\frac{b^8}{16 a^3}$

Question : If $8 a^3+27 b^3=16$ and $2 a+3 b=4$, then find the value of $16 a^4+81 b^4$.

Option 1: 26

Option 2: 30

Option 3: 28

Option 4: 32

Question : What is the fourth proportional to 7, 15, and 21?

Option 1: 29

Option 2: 30

Option 3: 48

Option 4: 45