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 Type-90 The Type-90, also known as the MZD-2, is a Chinese submunition used in the 122 mm Type-81 cluster rocket. It is made by Norinco. Type-81 rockets with Type-90 submunitions were used by Hezbollah against Israel in the 2006 Lebanon War, and they have been used in the Syrian Civil War as bombs dropped by weaponized Hezbollah quadcopters. Each Type-90 resembles a small cylindrical bell with a ribbon at one end. A plastic band full of 3mm steel spheres wraps horizontally around the middle of the cylinder. Inside is an armor-piercing shaped charge. Each Type-81 rocket contains 39 Type-90 submunitions.