Question: Is Lake Baikal bigger than the Great Bear Lake?
SPARQL:
PREFIX res: <http://dbpedia.org/resource/>
PREFIX dbo: <http://dbpedia.org/ontology/> 
ASK
WHERE {  
        res:Lake_Baikal dbo:areaTotal ?a1 . 
        res:Great_Bear_Lake dbo:areaTotal ?a2 .
        FILTER (?a1 > ?a2)
}