Angle trisection drawn through formula_25 to the semicircle, resulting in the intersection formula_28. The angle formula_48 generated by formula_49 and formula_50 is the angle formula_51 sought. Another means to trisect an arbitrary angle by a "small" step outside the Greek framework is via a ruler with two marks a set distance apart. The next construction is originally due to Archimedes, called a "Neusis construction", i.e., that uses tools other than an "un-marked" straightedge. The diagrams we use show this construction for an acute angle, but it indeed works for any angle up to 180 degrees. This requires three facts from geometry (at
Type 90 AFV Type 90 AFV The Type 90 is an armoured fighting vehicle produced by Chinese company Norinco; it is the successor for the Type 85 AFV of which it uses some components. The Type 90 series was developed for export, and consists of at least 10 different types; its industrial index is YW535. This new type is rather similar to its predecessors Type 85 AFV and Type 89 AFV, but the hull has a different shape, having a vertical lower side wall and a sloping upper side wall. Overall, the Type 90 is bigger and heavier, yet has a lower profile.