<Tr> <Th> Area </Th> <Td> 3 4 a 2 (\ displaystyle (\ tfrac (\ sqrt (3)) (4)) a ^ (2)) </Td> </Tr> <Tr> <Th> Internal angle (degrees) </Th> <Td> 60 ° </Td> </Tr> <P> In geometry, an equilateral triangle is a triangle in which all three sides are equal . In the familiar Euclidean geometry, equilateral triangles are also equiangular; that is, all three internal angles are also congruent to each other and are each 60 ° . They are regular polygons, and can therefore also be referred to as regular triangles . </P> <P> Denoting the common length of the sides of the equilateral triangle as a, we can determine using the Pythagorean theorem that: </P>

What is the size of the angles of an equilateral triangle