How to find an area of this figure? :

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What are the measures of ∠a, ∠b, ∠c and ∠d? explain how to find each of the angles. measure need asap

Sam makes his sales calls according to a pattern. he travels either north or south depending on the calendar. some of his past trips were as follows: on february 17, april 24, june 10, september 19, and november 3 he drove north. on february 28, may 25, august 22, november 20, and december 18, he drove south. describe sams' pattern. in which direction will sam drive on oct4 and oct 24?

Use circumcenter theorem to solve for the given values