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 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.