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 Ship-to-Ship Missile Type 90 Ship-to-Ship Missile The Type 90 Ship-to-Ship Missile (90式艦対艦誘導弾, SSM-1B) is a ship-launched anti-ship missile developed by Japan's Mitsubishi Heavy Industries that entered service in 1992. It is a naval version of the truck-launched Type 88 (SSM-1) missile, which in turn was developed from the air-launched Type 80 (ASM-1) missile. The Japan Maritime Self-Defense Force bought 384 of the missiles which it fitted to its "Akizuki", "Takanami", Hayabusa, and "Murasame"-class ships. With a range of , high subsonic speed and warhead, the Type 90 is similar to the US's RGM-84 Harpoon missile, and is replacing Harpoon on Japanese ships.