Step-by-step explanation:
Using Pythagoras ;
[tex]20=\sqrt{10^{2}+x^{2} } \\20^{2}=10^{2}+ x^{2}\\400 = 100 +x^{2} \\300 = x^{2} \\x =\sqrt{300}[/tex]
Please give me a brainliest answer
