Question

a rational number between 2.8 and 2.9

Answer 1

To answer this question, you need to find the mean, or the average.
So to do this you would add 2.8 and 2.9 toghether, making 5.7.
Next you divide the number by 2. 5.7/2 = 2.85.

So, The answer is 2.85

Please mark me as the brainliest.

Answer 2

$\bf \begin{cases} 2.\underline{8}\implies \cfrac{28}{1\underline{0}}\implies \cfrac{14}{5}\\\\ 2.\underline{9}\implies \cfrac{29}{10} \end{cases} \\\\\\ \textit{now, what's a rational between }\cfrac{14}{5}\quad and\quad \cfrac{29}{10}\quad ?$

notice, to convert to rational, you simply see how many decimals you have, and you use that many zeros for the "1" in the denominator

you lose the decimal point on the numerator, and add the zeros at the bottom to the 1

ahemm, in this case is only 1 decimal for each

so hmm well, what's a rational there

let's make both fractions, the same denominator

we'll do so, by multiplying 29/10 by the denominator of "5", top and bottom

and we'll multiply 14/5 by the denominator "10", top and bottom

so, we're really just using the denominators to cross-multiply the fractions, kinda

so  $\bf \cfrac{14}{5}\cdot \cfrac{10}{10}\implies \boxed{\cfrac{140}{50}} \\\\\\ \cfrac{29}{10}\cdot \cfrac{5}{5}\implies \boxed{\cfrac{145}{50}}$

now, notice, they're both the same denominators.. and surely you can tell what rational you can have in between