笔者在中考复习中曾布置了这样一道初一几何题,并要求同学们想一想能否用多种方法去求解。 题目如图1,已知,AB∥DE,∠ABC=140°,∠DEC=160°,求∠BCE。 真没想到,对这道如此简单的几何题,同学们倒真想出了好几种方法,采撷整理,以飨同学: 图1 图2 方法1 延长DE交BC于F,(图2)。 因为AB∥DE,∠ABC=140°,所以∠DFC=140°,因为∠DEC=160°,所以∠FEC=180°- The author had arranged such a first-year geometry question in the examination review, and asked the students to think about whether they could use a variety of methods to solve. The title is shown in Fig. 1. It is known that AB∥DE, ∠ABC=140°, ∠DEC=160°, and BCE. Unexpectedly, for this simple geometry problem, the students actually came up with several methods, which were collected and used to solve the problem: Figure 1 Figure 2 Method 1 Extending DE to submit BC to F, (Figure 2). Since AB∥DE, ∠ABC=140°, ∠DFC=140° because ∠DEC=160°, so ∠FEC=180°-