# Difference between revisions of "Equilateral triangle"

$[asy] pair A=(0,50),B=(43.301,-25),C=(-43.301,-25); draw(A--B--C--A); label("60^{\circ}",(-28,-16)); draw(anglemark(B,C,A,300)); label("60^{\circ}",(28,-16)); draw(anglemark(A,B,C,300)); label("60^{\circ}",(0,35)); draw(anglemark(C,A,B,300)); [/asy]$
An equilateral triangle is a triangle in which all sides have equal length and all angles have equal measure. Since a triangle has a total of $180$ degrees, each angle of an equilateral triangle has $60$ degrees.
One useful way to manipulate an equilateral triangle is to draw an altitude, which would divide it into two 30-60-90 right triangles. Using this, the area of an equilateral triangle can be found in terms of a side: $\frac{s^2\sqrt{3}}{4}$.