When the three sides of the triangle meet the conditions, the triangle is a blunt and sharp right tr

When the sum of the three sides of the triangle is greater than the third side, the triangle is obtuse and acute. When the sum of the three sides of a triangle satisfies the sum of the squares of the two right-angled sides equals the square of the third side, the triangle is a right-angled triangle.

Procedure: Let the three sides of the 3 corners be A, B, and C respectively

When the square of a + the square of b = the square of c is obtained from the Pythagorean theorem, the triangle is an RT triangle.

When the square of a + the square of b is less than the square of c.

The triangle is an obtuse triangle.

When the square of a + the square of b is greater than the square of c.

The triangle is an acute triangle.

It's a pity, it's so simple that there's no one here, sad?

Some symbols can't be typed and replaced with Chinese characters.,Understand?!

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This refers to the squares on both sides, not what you say!

Prerequisite: The sum of the two short sides and the long side, otherwise it cannot form a triangle.

The square of the two short sides and the square of the long side are right triangles;

The square of the two short sides and the square of the long side are acute triangles;

The squares of the two short sides and the square of the long sides are obtuse triangles;

Obtuse triangle: According to the cosine theorem, the sum of the squares of the 2 sides is less than the square of the other side (try it three times).

Right triangle: the Pythagorean theorem.

Acute triangle: Not the above two are like this.

For a triangle to fit the sum of any two sides, it must be greater than the third side.

The sum of any two sides must be greater than the third side, otherwise it will not be long enough to become a closed triangle.

The sum of any two sides must be greater than the third side!!

A 2 + b 2 = c 2 is a right triangle.

A 2 + B 2 > C 2 are acute triangles.

a^2+b^2

Let c be the longest side of the triangle, a and b are the other two sides, and the three sides satisfy a + b c, then the repentance is an obtuse triangle.

The analysis process is as follows:

A 2 + b 2 = c 2 is a right triangle.

A 2 + B 2 > C 2 are acute triangles.

A2+B2C2 is an obtuse triangle.

Triangles can be divided into acute triangles, right triangles and obtuse triangles according to the size of the angles, and acute and obtuse triangles are also called oblique triangles.

As long as one of the angles in a triangle is greater than 90 degrees, the triangle is an obtuse triangle, and according to the sum of the inner angles of the triangle is 180 degrees, the triangle can only have an obtuse angle.

When the square of the largest side of a triangle is equal to the sum of the squares of the other two sides, it is a right triangle according to the inverse theorem of the Pythagorean theoremWhen the square of the largest side of a triangle is greater than the sum of the squares of the other two sides

This triangle is an obtuse triangle.

Let the three sides of the triangle be a, b, and c.

When a b +c, the triangle is obtuse;

When a = b +c, the triangle is a right triangle;

When a b +c and b a +c and c b +a, the triangle is an acute triangle.

It can be proved with the cosine theorem:

If a is an obtuse angle, then cos a 0

2bc·cos a=（b²+c²-a²）＜0∴ b²+c²-a²＜0

a²＞b²+c²

Vice versa. The same can be said for right and acute angles.

Please adopt, thank you

Knowledge points: The three sides of the triangle are a, b, and c

1) If c = a + b then c = 90°;

2) If c >a +b, then c >90°;

3) If C 3

So, the condition for the triangle ABC to be an acute triangle is: 3

It should be the length of the third side c.

a, b, c should make the triangle abc satisfy each angle is less than 90°, because b is known to > a, so if abc is a right-angled triangle, there must be a right-angled side is a (the hypotenuse is the longest, a < b so it cannot be hypotenuse).

So, the maximum value of c should satisfy c and the minimum value of c should satisfy b so a +b

Suppose the third side is c

The square of a plus the square of b is equal to the square of c, the open root number is the root number, and the root number is 5, and c is the longest side.

The square of b minus the square of a is equal to the square of c, the open root number is the root number, and the root number is 3 and c is the shortest side.

So c is between root number 3 and root number 5, and the triangle holds.

It is true that an equilateral triangle is also an acute triangle. An equilateral pure lift triangle is a triangle in which three sides are of equal length. Whereas, an acute triangle is a triangle with three inner angles that are less than 90 degrees.

Because in an equilateral triangle, the three interior angles are all equal and 60 degrees, and 60 degrees is less than 90 degrees, so an equilateral triangle is also an acute triangle. In short, an equilateral triangle is just a special case of an acute triangle.

In an acute triangle, the sum of the lengths of any two sides is greater than the length of the third side. In addition, the angles in an acute triangle are more evenly distributed, so they are more stable and less prone to breakage than other types of triangles. In geometry, an acute triangle is a relatively simple triangle, so it is widely used in different fields such as architecture, engineering, aerospace, etc.

Special properties of equilateral trianglesThe peculiar property of an equilateral triangle is that the three interior angles are all 60 degrees and are equal; The three middle lines are equal in length and equal to half the length of the sides; Each inner bisector is also the high, middle, and angular bisector of the triangle; The radius of the inscribed circle is equal to the area of the triangle, and the area of the triangle is half a circumference; The radius of the circumscribed circle is equal to half the length of the side; Equilateral triangles are the largest of the hexagons; The sine, cosine, and tangent of an equilateral triangle are all equal to the root number 3. In conclusion, an equilateral triangle is a special triangle with symmetry and uniformity.

Right. In an equilateral triangle, the three angles are all 60 degrees, that is, the three buried corners are all acute angles, so they are acute triangles. Equilateral triangles are the most fingerical and stable structures.

Equilateral triangles are special isosceles triangles, so equilateral triangles have all the properties of isosceles triangles.

Equilateral triangular properties

1) An equilateral triangle is an acute triangle, and the inner angles of the equilateral triangle are all equal, and they are all 60°.

2) The centerline, high line, and angle bisector on each side of an equilateral triangle coincide with each other. (3-in-1).

3) An equilateral triangle is an axisymmetric figure that has three axes of symmetry, and the axis of symmetry is the straight line where the middle line, the high line, or the bisector of the angle on each side are located.

4) The center of gravity, inner, outer and vertical centers of an equilateral triangle coincide at one point, which is called the center of the equilateral triangle. (Four Hearts in One).

5) The sum of the distances from any point to three sides in an equilateral triangle is a fixed value. (equal to its height).

6) Equilateral triangles have all the properties of isosceles triangles. (Because equilateral triangles are special isosceles triangles).