The complete question in the attached figure
we know that
sin40° = opposite side / hypotenuse
opposite side =AC
hypotenuse = AB-------> 10 in
so
sin 40=AC/AB---------> AC=AB*sin 40-------> AC=10*sin 40
the answer is
AC=10*sin 40
we know that
sin40° = opposite side / hypotenuse
opposite side =AC
hypotenuse = AB-------> 10 in
so
sin 40=AC/AB---------> AC=AB*sin 40-------> AC=10*sin 40
the answer is
AC=10*sin 40