Question

draw a triangule ABC in which AB =8cm , ABC= 60° and BAC=90°

Mearse and write down
1}ACB
2}AC
3}BC

Answer 1

"Mearse"?? You mean measure?

so, draw your triangle and measure. What did you get?
You have a 30-60-90 right triangle, so the sides are in the ratios
1 : √3 : 2