# Author: Bernat Requena Serra

## Perimeter of a triangle

Select your language EnglishSpanish The perimeter of a triangle is the sum of its three sides. The formula for the perimeter of a triangle depends on the type of triangle. But there is a...

## Area of a triangle

Select your language EnglishSpanish Finding the area of a triangle is depending on the type of triangle or which sides and angles we know. The most common formula for finding the area of a...

## Area of a Triangle Using the Base and Height

Select your language EnglishSpanish The area of any triangle can be calculated by knowing one side and the height (or altitude), associated with that side. This side serves as the base. In fact the...

## Basic Elements of a Triangle

Select your language EnglishSpanish The basic elements of a triangle are: Vertices: points where two sides meet. It has 3 vertices (A, B, and C). Sides: line segments that join two consecutive vertices of...

## Similar triangles

Select your language EnglishSpanish In Euclidean geometry, two objects are similar if they are the same shape, regardless of their size. Two triangles are similar if, and only if, their angles are congruent (equal)...

## Euler Line

Select your language EnglishSpanish In any non-equilateral triangle the orthocenter (H), the centroid (G) and the circumcenter (O) are aligned. The line that contains these three points is called the Euler line. In an...

## Thales’ Theorem

Select your language EnglishSpanish There are several theorems that are attributed to Thales of Miletus, we are going to focus especially on two of them: Thales’ Theorem Thales’ Theorem is a special case of...