119: Area of Triangles

From the Amazingly Amazing Fake Martin Gardner Twitter Account:

Which has the larger area?

• A triangle with sides of 3, 4, and 5.
• A triangle with sides of 300, 400, and 700.

Challenge

• Change one dimension of the 300, 400, 700 triangle to give the two triangles the same area.

"Which has the larger area? A triangle with sides of 3, 4, 5, or a triangle with sides of 300, 400, and 700?" p17 Riddles of the Sphinx
— Martin Gardner tweet (@WWMGT) April 27, 2014