Motor company sells cars and makes profits of $1,000,000.
Motor company also buys a chicken farm. The chicken farm is successful that quarter and makes a profit of $1000.
Profits for the company from the motor business: 99.9%
Profits for the company from the chicken business: 0.1%
So the chicken business is insignificant. If the motor business profits go down the company will suffer. If the chicken business suffers or succeeds, it doesn't matter. Got it?
Now, when somebody says the X business has entered into hotel / chicken farm / rubber plantation business. Check how much it contributes to the profits compared to the core business. New venture's contribution could be 0.1%.