Someone please help with this question its urgent

What is the length of the unknown leg in the right triangle ?

Apackage of five erasers cost 0. $.39 at this rate how many how much would 60 erasers cost in dollars and cents

This is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 5 terms.