Question

the mean proportional between 1
4/5 and 4/5

Answer 1

mean proportional * mean proportional = first term+third term
$x {}^{2} = 14 \div 5 + 4 \div 5 \\ x {}^{2} = 2.8 + 0.8 \\ x {}^{2} = 3.6 \\ x = \sqrt{3.6} \\ x = 1.897$
This is the mean term in decimal.
The answer can be also in fraction
But if you will solve the fraction , the answer will be same as mine answer.