What is the difference between composition and ecomposition? can you use them to find the area of a polygon?

Use set builder notation to represent the following set: { -3, -2, -1, 0}

Write the fraction or mixed number and the decimal shown by the model

In the figure below, ∠dec ≅ ∠dce, ∠b ≅ ∠f, and segment df is congruent to segment bd. point c is the point of intersection between segment ag and segment bd, while point e is the point of intersection between segment ag and segment df. the figure shows a polygon comprised of three triangles, abc, dec, and gfe. prove δabc ≅ δgfe.