Question

the fourth proportional to. 8.1,1.2,2.7

Answer 1

Here is your answer
Let fourth proportional is x
so 8.1 :1.2 : 2.7 : x
Now by using formula ,
$8.1 \times x = 1.2 \times 2.7 \\ x = 1.2 \times 2.7 \div 8.1 \\ x = 0.4$
Hope it helps you more