Answer:
[tex]x = 6.25[/tex]
Step-by-step explanation:
Since the quadralterials are similar and the perimeter has a ratio of 12:5 the sides also have a ratio of 12:5.
Set up the proportion.
[tex] \frac{12}{5} = \frac{15}{x} [/tex]
[tex]12x = 75[/tex]
[tex]x = 6.25[/tex]
