Answer: 3.75
Step-by-step explanation:
[tex]b = 5\\c=6.25\\a^{2} + b^{2} = c^{2} \\a^{2} +5^{2} = 6.25^{2} \\a^{2} + 25 = 39.0625\\a^{2} = 14.0625\\\sqrt{a^{2}} =\sqrt{14.0625} \\a = 3.75[/tex]
The missing side length is 3.75
