We can start off by finding the area of the larger triangle
[Formula : 1/2 x Base x height]
1/2 x 6 x 6 = 18
Now we can find the area of 6 small triangles
1/2 x 1 x 1 = 1/2 ( 1 small triangle )
1/2 x 6 = 3 ( 6 small triangles )
Total area = large triangle + 6 small triangles
18 + 6 = 24 cm square