A triangle is a two-dimensional figure with three edges and the same number of vertices. This is one of the main forms in geometry. The object has three angles; their total degree measure is always 180 °. Peaks are usually denoted in Latin letters, for example, ABC.
Theory
Triangles can be classified according to various criteria.
If the degree measure of all its angles is less than 90 degrees, then it is called acute-angled, if one of them is equal to this value - rectangular, and in other cases - obtuse.
When a triangle has all sides of the same size, they call it equilateral. In the figure, this is marked with a mark perpendicular to the segment. The angles in this case are always 60 °.
If only two sides of the triangle are equal, then it is called isosceles. In this case, the angles at the base are equal.
A triangle that does not fit the two previous options is called versatile.
When they say that two triangles are equal, this means that they have the same size and shape. They also have the same angles.
If only degree measures coincide, then the figures are called similar. Then the ratio of the respective sides can be expressed by a certain number, which is called the coefficient of proportionality.
The perimeter of a triangle across an area or side
As with any polygon, the perimeter is the sum of the lengths of all sides.
For a triangle, the formula looks like this: P = a + b + c, where a, b and c are the lengths of the sides.
There is another way to solve this problem. It consists in finding the perimeter of the triangle through the area. First you need to know the equation connecting these two quantities.
S = p × r, where p is the semiperimeter and r is the radius of the circle inscribed in the object.
It is very simple to convert the equation into the form we need. We get:
p = S / r
Do not forget that the current perimeter will be 2 times larger than received.
P = 2S / r
Such examples are simply solved.