1. The side spread diagram is a semicircle, and its perimeter is the perimeter of the bottom circle, so the radius of the bottom circle is half that of the side spread diagram. Let the radius of the bottom circle be r, then the radius of the semicircle in the side expansion diagram is 2R, and find the surface area of the cone = pi * (the square of the square 2R of r/2) =a, and the square of R =a/3 pie can be obtained, and the diameter can be calculated.

2。 The side is an isosceles trapezoid with an upper bottom of 8, a lower bottom of 18, a waist length of 13 and a height of 12, so its area is (818) *12 =12.