Triangle and its types
The triangle is defined as a closed triangular shape, its three sides are straight, and it has three angles. The triangle is classified according to the type of its angles into the acute-angled triangle; If all of its angles are acute (that is, their measure is less than 90 degrees), – and the triangle is isosceles in which the measure of each angle is 60 degrees – and the triangle is right-angled; If one of its angles is right (that is, its measure is 90 degrees), and the triangle is obtuse; If one of its angles is obtuse (that is, its measure is greater than 90 and less than 180 degrees), the angle is called by one letter, such as the angle x, or by three letters, such as the angle (xx yy).
A triangle is classified according to its sides into an equilateral triangle; If all of its sides are equal in measure and an isosceles triangle; If only two sides are equal in measure, and a scalene triangle; If all sides differ in measurement.
Knowing the triangle
A triangle is formed if the three points in it are not straight, that is, the sum of the lengths of any two sides of the triangle is greater than the length of the third side, and this is verified in two ways; The first is to draw a straight line between any two of the three points that make up the triangle. If this line passes through the third point, then the three points lie on one straight line, and do not form a triangle. The second method is to calculate the distances between the three points in binary, if the sum of the two smallest distances is The two of them are equal to the greater distance, so the points are on the same line.
Triangle angle laws
The measure of an exterior angle from a triangle is equal to the sum of the measures of the two remote angles, and it is known that the sum of the measures of the angles of any triangle equals 180 degrees, and the two complementary angles have the sum of their measures 180 degrees, and the two complementary angles have the sum of their measures 90 degrees, and in an congruent triangle the legs The base angles are equal in measure, and if a column from the vertex of an isosceles triangle is perpendicular to the base, it bisects it.
One of the theorems that studies the triangle states: “The length of the line segment joining the midpoints of two sides of a triangle is equal to half the length of the third side and is parallel to it.” There is a right-angled triangle theorem that states: “The length of the line segment joining the vertex of the right and the midpoint of the hypotenuse in a right-angled triangle is equal to half the length of the hypotenuse.” The hypotenuse is the longest straight segment of the triangle, corresponding to the right angle.
To draw a triangle with vertices (a d c), we draw the straight segment connecting any two vertices. An arc from point C, and then we draw from point D in the same way, provided that the compass hole is equal to the length of the piece (Da) and be 4 centimeters, and the two arcs intersect forming point A, so we connect point A and point D by a straight line, and between point A and point C , a triangle is formed.