How do you solve this inequality

What is the difference between the predicted value and the actual value

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.

A. 530 ft^2 b. 500 ft^2 c. 470 ft^2 d. 450 ft^2