You can put this solution on YOUR website! Basic fact:
The altitude of an equilateral triangle bisects the side on which it stands and forms right angled triangles with the remaining sides.
It would have been better if I could have drawn this here but as I cant I will try to explain it in words.
We have the length of each side = 12cm
Therefore the altitude bisects the side on which it stands into 2 equals each measuring 6cm
Hence one half of the triangle being a right angled triangle will have the following measurements
Hypotenus = side of the triangle = 12cm
Base= half of the side on which the altitude stands = 6 cm
Therefore as per the Pythagoras theorem
=
=
=
Therefor the Altitude =
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