(1) The base of the wedge is an isosceles right triangle in a vertical plane.(2) Mathematicians sometimes say that A is an arbitrary isosceles triangle, but all they mean is that A could be any such triangle.(3) isosceles triangle(4) The base angles of an isosceles triangle are equal.(5) This is the u251cu00f6u251cu00e7u251cu2510alternateu251cu00f6u251cu00e7u251cu00fb solution to constructing the isosceles triangle with the base of the square as one side, using only a straightedge.(6) First construct an isosceles triangle whose base angles are double the vertex angle.