Fortune magazine cited the head of the world’s largest technology corporation as saying he planned to donate his estimated $785 million fortune to charity – after paying for his 10-year-old nephew’s college education. “You want to be the pebble in the pond that creates the ripples for change,” Cook told the magazine. Fortune estimated Cook’s net worth, based on his holdings of Apple stock, at about $120 million. The 54-year-old CEO’s revelation in Fortune’s lengthy profile of him is an example of the increasingly public philanthropy of the world’s richest people.