Question 404734
the two diagonals in a square are at {{{right}}}{{{ angles}}} to each other;

 hence if one diagonal has a {{{slope = - ( 2/5 )}}}, the other must have {{{slope = + ( 5/2 )}}}

Explanation:

 We know that {{{if }}}{{{two }}}{{{lines}}} are at right angles to each other, {{{product}}} of their slopes {{{must}}} be equal to {{{( - 1 )}}}. 

check:

{{{-(2/5)( 5/2 )=(-(2*5))/(5*2) = -10/10=-1}}}


hence slope of the other diagonal {{{ BD = 5/2}}}