Widen Spell [Metamagic]
Benefit: You can alter a burst, emanation, line, or spread shaped spell to increase its area. Any numeric measurements of the spell's area increase by 100%. A widened spell uses up a spell slot three levels higher than the spell's actual level.
Spells that do not have an area of one of these four sorts are not affected by this feat.
Source: SRD 3.5 Feats