The Leshan Giant Buddha is the tallest Buddha statue in the world, with a height of 71 meters. The ear length of the giant Buddha is about the height of the Buddha statue (7/71), and about the length of the head (10/21). How many meters is the head length of the Leshan Giant Buddha?
乐山大佛是世界上最高的佛像，高71米．大佛耳长约是佛像高的(7/71)，又约是头长的(10/21)，乐山大佛的头长约是多少米？
<result>14.4</result>