Question

I Need Help Pls ASAP

Answer 1

We know that
∠ECD=∠ACB------> given in the problem
∠DEC=∠CAB------> 90°
so
∠EDC=∠ABC

therefore
triangles EDC and ABC are similar
So
the ratio of the legs are equal

 $\frac{x}{9} = \frac{140-x}{81} \\ 81*x=9*(140-x) \\ 81x+9x=1260 \\ 90x=1260 \\ x=14$

$AC=140-x \\ AC=140-14 \\ AC=126$

the answer is
AC is equal to 126