Question 1135589
rectangle {{{ABCD}}} has dimensions of {{{7}}} units by {{{5}}} units

if you have rectangle, the length of its diagonals is same


diagonal divides rectangle into two congruent right triangles where diagonal is hypotenuse, and dimensions {{{7}}} and {{{5}}} are legs

so, use Pythagoras theorem to find the length of its diagonal

{{{d^2=7^2+5^2}}}

{{{d^2=49+25}}}

{{{d^2=74}}}

{{{d=sqrt(74)}}}

{{{d=8.6}}} units