HELP ASAP PLEASE THIS IS MATH

Answer:
[tex]\displaystyle 8,1[/tex]
Step-by-step explanation:
Use the Pythagorean Theorem twise [first time for the reflexive edge and the second time for the longer leg of the other triangle]:
[tex]\displaystyle a^2 + b^2 = c^2 \\ \\ a^2 + 5^2 = 10^2 \hookrightarrow 100 = 25 + a^2 \hookrightarrow \sqrt{75} = \sqrt{x^2}; 5\sqrt{3}\:[or\:8,6602540378...] = a \\ \\ \\ \\ a^2 + b^2 = c^2 \\ \\ x^2 + 3^2 = 5\sqrt{3}^2 \hookrightarrow 75 = 9 + x^2 \hookrightarrow \sqrt{66} = \sqrt{x^2}; \sqrt{66}\:[or\:8,1240384046...] = x \\ \\ \boxed{\boxed{8,1 \approx x}}[/tex]
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