Right angle Right angle In geometry and trigonometry, a right angle is an angle of exactly 90° (degrees), corresponding to a quarter turn. If a ray is placed so that its endpoint is on a line and the adjacent angles are equal, then they are right angles. The term is a calque of Latin "angulus rectus"; here "rectus" means "upright", referring to the vertical perpendicular to a horizontal base line. Closely related and important geometrical concepts are perpendicular lines, meaning lines that form right angles at their point of intersection, and orthogonality, which is the property of forming right angles, usually applied
Type 90 Kyū-maru leading to higher per unit costs than comparable models from NATO countries such as the M1 Abrams and the Challenger 2. Development of upgrades to the Type 90 suffered both as a result of limited budget, which caused procurement delays, and funding prioritization in favor of the Type 10 Main Battle Tank. Due to a perception that Type 90s are unsuited to operations in the tight confines of Japan's urban areas, they are preferentially assigned to the JGSDF Fuji School Brigade and the 7th Armored Division based in Hokkaido, where there is sufficient room for maneuver. With the exception of