三角形的研究元素通常有:边、角、高、角平分线、中线、面积等;等腰三角形是特殊的三角形,它的三条边中只要任意两条相等就是等腰三角形;它的三个角中只要任意两个角相等就是等腰三角形;等腰三角形又有锐角三角形、直角三角形、钝角三角形之分,它腰上的高可能作在腰上也可能作在腰的延长线上,所以,等腰三角形的计算及证明往往需要数形结合、分类讨论、从特殊到一般、归纳探究.一、关于边 Triangle research elements usually have: edge, angle, high, angle bisector, center line, area, etc .; isosceles triangle is a special triangle, its three sides as long as any two equal is the isosceles triangle; its three corners As long as any two equal angles is the isosceles triangle; isosceles triangle and acute triangle, right triangle, obtuse triangle points, the waist may be high on the waist may also be in the extension of the waist line, therefore, Isosceles triangle calculation and proof often need to form a combination of classification discussion, from special to general, to explore.