<PRE><B>Question 1063973</B>
The height of an equilateral triangle is a perpendicular bisector, therefore
:
(x/2)^2 + 12^2 = x^2
:
x^2 - (x^2/4) = 144
:
3x^2/4 = 144
:
3x^2 = 576
:
x^2 = 192
:
x = 13.8564 cm
:
</PRE>