How to distinguish acute angle from obtuse angle

The difference between acute angle and obtuse angle is as follows:

1, acute angle: refers to an angle (right angle) greater than 0 and less than 90, and acute angle is a bad angle.

2. Oblique angle: an angle greater than (90) and less than right angle (180).

Acute and obtuse angles can be distinguished according to whether their degrees are greater than 90 degrees or less than 90 degrees. If it is a plan, it can be easily identified directly with a right-angled triangular ruler. If one right-angle side of the right-angle triangular ruler is attached to one side of the measured angle, and the other side of the angle is outside the other right-angle side of the right-angle triangular ruler, the angle is obtuse.

If it is attached to the other side of the right-angled triangular ruler, it is a right angle, and if it is inside the right-angled triangular ruler, it is an acute angle.

way

1, measure.

You can measure it with a protractor. An angle greater than 0 degrees and less than 90 degrees is an acute angle, and an angle greater than 90 degrees and less than 180 degrees is an obtuse angle.

2. Comparative method.

An angle larger than a right angle is called an obtuse angle, and an angle smaller and sharper than a right angle is called an acute angle. I do not see any at all. You can compare it with the right angle in a triangle.

3. Look at their nature. 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 in the first quadrant, but all the angles in the first quadrant are not necessarily acute angles. The sum of two obtuse angles must be greater than the right angle and less than the fillet. The obtuse angle must be in the second quadrant, but the angle of the second quadrant is not necessarily obtuse.

Expand one's knowledge

Oblique angles and acute angles are widely used in geometry.

1. In solid geometry, obtuse angles and acute angles can be used to describe plane or solid structures with different angles.

2. In analytic geometry, obtuse angles and acute angles are often used to describe various curves and surfaces.

3. In the field of architectural design, geometry also plays a key role. Architects often use geometry to determine the design of buildings, including shape, size, proportion and lines.

4. The application of geometric figures in photography is also closely related to the photographer's perspective and thinking. Regular geometric patterns often have obvious repetition in shape, color and line, showing a certain pattern effect with regular changes.