新授“三角形内角和”一节时,其课堂练习我是分以下三段安排的: 第一段:尝试性的基本练习.习题如下: 1.求下列各三角形未知角的度数. (1)在一个三角形中,∠1=32°,∠2=48°,求∠3. (2)一个直角三角形,它的两个锐角都相等.这直角三角形每个角各是多少度? (3)在一个三角形中,三个锐角都相等,每个角是多少度? In the new chapter entitled “Triangle and Corner of Triangle”, I will classify it in the following three sections: The first paragraph: The tentative basic exercise Exercises are as follows: 1. Find the following degrees of unknowns in each triangle. (1) In a triangle, ∠1 = 32 °, ∠2 = 48 °, and ∠3. (2) A right-angled triangle with two acute angles equal to each other. How many degrees are each of these right-angled triangles? In a triangle, three acute angles are equal, each angle is how many degrees?