Question 898508
That height cuts the triangle into two special triangles of the 30-60-90 type.  Assign a variable to the hypotenuse, example, x; and then the short leg is x/2, which you know based on the special triangle resulting from the equilateral triangle.  


{{{highlight_green((x/2)^2+26^2=x^2)}}}, Pythagorean Theorem.  x is ALSO the length of one side of the equilateral triangle.


The inches quantity will use 1 inch = 2.54 centimeter, and 100 centimeters = 1 meter.