Set up a proportion for the length and width of each shape:
[tex] \frac{3}{5} = \frac{x}{3} [/tex]
The numerator represents the length, and the denominator represents the width of the shapes.
Cross multiply the two fractions:
[tex]5x = 9[/tex]
Divide both sides by 5 to get x by itself:
[tex]x = 1.8[/tex]
The missing length is 1.8 inches.
