A child rolls a disk with a radius of 10cm on a non-slip plane track, and stops when it starts to tangent to the inclined plane BC, where AB=80cm, and the angle between BC and the horizontal plane is 60.

(1) Find the route length (accurate to 0.1cm) through which the center of the disc passes when rolling on AB; );

The length of the route through which the center of the circle passes, that is, the disc rolls once on AB, and the length is 3.14 * 20 = 62.8cm..

(2) What is the length of the route that the center of the disc passes when it rolls from point A to stop when it is tangent to BC? (accurate to 0. 1cm).

When the disc rolls from point A to point E and is tangent to BC, the tangent point between the disc and AB is d, and the distance of DB is found.

Even OD\OE\DE\OB, it is easy to prove that angle DOB= angle EOB=30 degrees.

OB= 10* root number 3/3=5.8

80-5.8 = 74.2 cm