How do we do pemdas? What do each letter stand for?

Pepe is going to spin the following spinner 800 times. the spinner is divided into equal sections.a. exactly 160 timesb. clost to 160 times but probably not exactly 160 timesc. exactly 640 timesd. close to 640 times but not probably not exactly 640 times. me

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.

What are the measures of angles a, b, and c? show your work and explain your answers. 25 points