A triangle has two equal sides, and the third side is 1.5 times any of these sides. If the perimeter of the triangle is 14 units, then the area of the triangle is ________ square units.
1
\( 3 \sqrt{3}\)
2
\( 3 \sqrt{7}\)
3
\( 4 \sqrt{7}\)
4
\( {3 \over2} {\sqrt{7}}\)