A circle has a mass of 3 grams and a square has a mass of 2 grams. what is the mass of a triangle in grams.

The scale is balanced so both sides need to weigh the same amount.

On the left side you have:

6 squares, 3 circles and 2 triangles

On the right side you have:

3 squares, 2 circles and 5 triangles

Sunday equal amounts of each from both sides you would have:

3 squares and 1 circle in the left and 3 triangles in the right.

So we know the 3 squares and 1 circle = 3 triangles:

3 squares x 2 grams = 6 grams

1 circle x 3 grams = 3 grams

6 + 3 = 9 grams

9 grams / 3 triangles = 3 grams per triangle.,