Wow. They worked hard to trip you up on this one!
First, don't let the word "decompose" spook you.
We are basically dividing 1 sq m into 9 equal pieces.
So each piece is 1/9 of a sq m.
Then, we make each small piece 1/2 of a square.
1/9 x 1/2 = 1/18.
Each triangle will be 1/18 of a sq meter.
So 6 will be 6/18 or 1/3 of a sq. meter
To figure 1.5 square meters out of triangles...
There are 2 triangles per small square, and 9 small squares per sq meter - and then you add 50% more.
(2 x 9) + (2 x 9 x .5) = 27 triangles