Why is it necessary to take a chance

You won't know what the outcome will be and you never will unless you try.

Without getting overly metaphorical, the best way to answer this is by saying that taking a chance is the literal only way to improve.

Taking chances is what gives us results, and results are what moves us forward in life, chances give us opportunities to better ourselves, and even if the attempt fails, you can learn from your mistake and take that chance again.