Given :
A rectangle has a diagonal of 15cm and a width of 9cm
The diagonal represents a hypotenuse
See the following figure:
Using the Pythagorean to find length
diagonal = d = 15 cm
width = w = 9 cm
Length = l
So,
[tex]l^2+w^2=d^2[/tex][tex]\begin{gathered} l^2+9^2=15^2 \\ l^2+81=225 \\ l^2=225-81=144 \\ \\ l=\sqrt[]{144}=12 \end{gathered}[/tex]
So, the length of the rectangle = 12 cm
