Haley constructed this 10-sided polygon using triangles,
what is the minimum number of triangles required to construct this figure?

answer:

8

step-by-step explanation:

recall that in the case of regular polygons, the number of triangles which make up the entire area of the polygon is given by (n-2) where n is the number of sides (or vertices) of the regular polygon.

in this case, you have a regular   10-sided polygon, hence n=10,

therefore the number of triangles = 10 - 2 = 8 triangles.