What is an acute angle, a right angle, an obtuse angle?

The definitions of acute angles, obtuse angles and right angles are as follows:

1. Acute angle: refers to an angle less than 90°, that is, an angle smaller than a right angle. For example, a 30-degree angle and an 80-degree angle are both acute angles.

2. Right angle: refers to an angle whose size is equal to 90 degrees, that is, the angle formed by two rays that intersect each other. For example, both a square and a rectangle contain four right angles.

3. Obtuse angle: refers to an angle greater than 90 degrees but less than 180 degrees, that is, an angle larger than a right angle. For example, an angle of 110 degrees and an angle of 150 degrees are both obtuse angles.

The use of triangles in life

1. Triangles are widely used in life, from simple table and chair supports to complex bridge structures, they are inseparable from the presence of triangles. . House supports: Many house supports are designed with triangular structures, such as roofs, stairs and suspended ceilings. This is because triangles provide stability and are able to effectively support and secure the weight of the building.

2. In the structure of the bridge, many key parts adopt triangular structures, such as supports and expansion joints. This design can increase the bridge's load-bearing capacity while ensuring its stability and durability. The track and roller system of a folding door are actually tiny triangular structures that nest into each other to allow the door to open and close smoothly.

3. A tripod is an essential tool in photography. It contacts the ground through three fulcrums to form a stable support platform. This design can effectively prevent the camera from shaking during shooting and improve the clarity of photos. The bicycle frame is a typical triangular structure. This design makes the bicycle more stable during driving.

4. At the same time, the bicycle wheels also adopt a circular design, which can reduce friction and vibration during driving. The bracket of the TV antenna also adopts a triangular structure. This design can effectively improve the signal receiving capability of the antenna while ensuring its stability and durability.

5. The design of the lightning rod uses the principle of tip discharge to guide lightning to itself and introduce the current into the ground through the triangular structure of its tip. This design can effectively protect buildings from lightning.