The following question came near to being set in a recent examination: The area of a triangle is calculated from the formula
![](//static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20180308053856430-0997:S0025557200030163:S0025557200030163_inline01.gif?pub-status=live)
where 2s = a + b + c. It is known that the measurements of the sides are correct to within 1 per cent. Find the greatest possible percentage error in the area.