The hanger diagram ideally should be in balance with all the shapes hung on it.
On the left side, it shows that the circles are 9 grams and the squares are 12 grams. The triangles are 2t grams. Therefore, on the left side we have,
9 + 12 + 2t
On the right side, it shows the circles are 6 grams and the squares are 6 grams, while the triangles are 5t grams. Therefore on the right side we have
6 + 6 + 5t.
For the hanger to be in balance, we should have