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 Kyū-maru tank made Type 90 more challenging to operate outside Hokkaido. Some politicians therefore criticized the effectiveness of Type 90 due to difficulty in transportation. In fact, more than 65% of major bridges in Japan were still considered passable for Type 90 while overseas main battle tanks such as Challenger 2 and Leopard 2 could only use 40% of bridges in Japan. Type 90 Kyū-maru The is a main battle tank (MBT) of the Japan Ground Self-Defense Force (JGSDF). It was designed and built by Mitsubishi Heavy Industries as a replacement for all deployed Type 61 and Type 74 tanks, and