So there are 2 big triangles
You could find the areas of all 2 triangles and add them all up, because those 2 triangles make up the shaded region
The formula for area of a triangle: a=1/2bh
The length of the triangles are 6, b/c 3+3 is 6
Both of their heights are 4
a=1/2bh
a=1/2*4*6
a=2*6
a=12 units squared
that is the area of one triangle
both triangles are equal, so multiply 12 by 2, and you get 24
24 units squared
hope this helps!
