Introduction to right angle:
In geometry and trigonometry, right angles are also called positive angles, which are 90 degrees. It is relative to a quarter of a circle (that is, a quarter of a circle), and two right angles are equal to a half angle (180). An angle smaller than a right angle is called an acute angle, and an angle larger than a right angle but smaller than a right angle is called an obtuse angle. A right angle is equal to 90 degrees, and the symbol is Rt∞.
Angle:
A measure of the amount of rotation when either of two intersecting lines overlaps the other. Rotation is on the plane of two straight lines and around the intersection. Angle is the unit of measuring angle, and the symbol is 0. A fillet is divided into 360 equal parts, and each part is defined as 1 degree (1 degree).
Use the number 360, because it is easily divisible. 360 has 22 real factors besides 1 and itself, including 2 to 10 except 7, so many special angles are integers. In practical application, the angle of an integer is accurate enough. Sometimes more accurate measurements are needed, such as astronomy or the latitude and longitude of the earth.
Other angles in mathematics:
1, acute angle
The acute angle refers to an angle greater than 0 and less than 90, and the acute angle is the lower angle. The sum of the two acute angles is not necessarily greater than the right angle, but it must be less than the right angle. The acute angle must be the first quadrant angle, and the first quadrant angle is not necessarily the acute angle. In an acute triangle, every internal angle is acute, and the sum of any two internal angles is greater than the right angle; Each side is sandwiched between the product sum quotient of its adjacent sides and the cosine of the included angle.
2. Boxer angle
The light rotates around its endpoint. When the starting edge and the ending edge are on the same straight line and in opposite directions, the angle formed is called a right angle. 1boxer =180+360k (k ∈ z) boxer is not a straight line, but two rays on a straight line. It should be understood that any "angle" is composed of two rays with a common vertex, and a right angle is no exception.
It's just that two rays forming a right angle are on a straight line. To be exact, a right angle is the angle formed by two rays in opposite directions on the same straight line, and you can't confuse straight lines with rays. A right angle consists of two right angles.