Add all of the sides together. Make sure to use a common denominator because you are adding fractions. Don't forget your unit label (feet)
[tex] \frac{21}{8} [/tex] + [tex] \frac{31}{2} [/tex] + [tex] \frac{21}{2} [/tex]
[tex] \frac{21}{8} [/tex] + [tex] \frac{124}{8} [/tex] + [tex] \frac{84}{8} [/tex]
[tex] \frac{229}{8} [/tex] feet
