In a message dated 24/01/2007 13:25:57 GMT Standard Time, philip@konti.demon.co.uk writes: Given you have the lengths of the three sides, a, b and c, the area can be found from the square root of s(s-a)(s-b)(s-c), where s is half the perimeter. ______________________________________________________________________ This may be of interest "Elementary text book for young surveyors and levellers" By Henry James Castle 1856 See http://preview.tinyurl.com/3cpnuj Regards Stan Mapstone