Euclidean geometry equal (SAS), or two angles and a side equal (ASA) (Book I, propositions 4, 8, and 26). Triangles with three equal angles (AAA) are similar, but not necessarily congruent. Also, triangles with two equal sides and an adjacent angle are not necessarily equal or congruent. The sum of the angles of a triangle is equal to a straight angle (180 degrees). This causes an equilateral triangle to have three interior angles of 60 degrees. Also, it causes every triangle to have at least two acute angles and up to one obtuse or right angle. The celebrated Pythagorean theorem (book I,
Gewehr 98 internal magazine boxes feature an internal magazine length of to store maximal overall length 7.92×57mm Mauser cartridges without dimensional issues. The cartridges are stored in the magazine box in a staggered column at a stacking angle of 30 degrees, so viewed from the end, three cartridges touching each other form the points of an equilateral triangle. The magazine can be loaded with single rounds by pushing the cartridges into the receiver top opening or via stripper clips. Each stripper clip can hold 5 rounds to fill the magazine and is inserted into clip guides machined into the rear receiver bridge.