THIS is a good elementary text-book, founded on the work by M. E. Lagout (“Takimetry”), which we have already noticed (NATURE, vol. xvi. p. 226). The ground covered by the work before us is not quite ...

Discusses the properties and types of triangles, explaining that a triangle is a closed figure with three sides and angles. It categorizes triangles into equilateral, isosceles, scalene, obtuse, right ...