Question 17583
you would use Pythagorus theorem:
square on hypotenuse=sum of squares of other two sides.
In your case diagonal is hypotenuse.
so if (d)is diagonal and x and y the two sides it connects
{{{d^2=x^2+y^2}}}
add{{{x^2}}} and{{{y^2}}}
then find{{{sqrt(d^2)}}}
Pete