Terumah: “The Aron”

The Aron was 2.5 amahs in length by 1.5 amahs wide [Shemos 25:10]. An amah is six tefachim.

Question: What was the area of the base of the Aron in square tefachim?

Answer: 

2.5 x 6 = 15

1.5 x 6 = 9

9 x 15 = 135 square tefachim