Question 862251
Dimensions of the rectangle are w and 10w.  The diagonal forms two congruent triangles, each a right triangle.


diagonal, d.
{{{d^2=(w)^2+(10w)^2}}} based on pythagorean theorem.
{{{d=sqrt(w^2+100w^2)}}}
{{{d=w*sqrt(1+100)}}}
{{{highlight(d=w*sqrt(101))}}}