As shown in the figure, fold a pair of triangular plates together so that the vertices of the right angle coincide with point O, then ∠ AOC + ∠ DOB=______ Degree

Let ∠ AOD = a, ∠ AOC = 90 ° + A, ∠ BOD = 90 ° - A, so ∠ AOC + ∠ BOD = 90 ° + A + 90 ° - a = 180 °. So the answer is 180 °

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