课题学习:三角形三边垂直平分线交于一点,这一点称为三角形的外心,外心到三角形三个顶点的距离相等;三角形三个角平分线交于一点,这一点称为三角形的内心,内心到三角形三边距离相等。请问三角形三边中线是否也交于一点呢? Topic study: the triangle perpendicular to the bisector to pay a little, which is called the outer triangle, the outer center of the triangle to the three vertices of the same distance; triangle bisect the angle of the three corners, which is called the heart of the triangle , The inner triangle to the triangular distance equal. Will the triangular trilateral centerline also pay a little?