Yihongyuan: [final]

Assuming Yihongyuan represents a circle with a diameter of 1 unit, its area (A) can be calculated using the formula:

During the Tang dynasty (618 - 907 CE), the concept of Yihongyuan gained further attention, as mathematicians and scholars began to explore its implications in more depth. The celebrated mathematician Zu Chongzhi (429-501 CE), known for his groundbreaking work on pi, is believed to have written about Yihongyuan in his treatise "Zu Chongzhi's Mathematical Works." Yihongyuan [Final]

where r is the radius. Given that the diameter is 1 unit, the radius (r) is 1/2 unit. Assuming Yihongyuan represents a circle with a diameter