1. The length of a circle around the tree is the circumference of the trunk, so 12.56m is the circumference of 10, so the circumference of the trunk is 1256m. According to the formula of perimeter l=πd, that is, d=l/π, π≈3. 14, so the trunk radius D = 654438.

2. The minute hand rotates every hour to form a circle, so the distance traveled by the tip of the minute hand is the circumference of the circle, the radius of the circle is 100 mm, the circumference l=πd=3. 14*200=628 (mm), and the area of the circle is S = π * r * r = 3.

So every hour, the tip of the minute hand passes 628 mm, and the swept area is 3 1400 square mm.