Answer:
60
Step-by-step explanation:
we know by Pythagoras theorem that
[tex]a^2+b^2=c^2[/tex]
with c the hypotenuse
so in our triangle we have
[tex]a=80\\\\b=b\\\\c=100\\\\\\\\(80)^2+b^2=(100)^2\\\\b^2=(100)^2-(80)^2\\\\b^2=(100-80)(100+80)\\\\b^2=20(180)\\\\b^2=3600\\\\b^2=60^2\\\\b=60[/tex]
