Straight lines of ABCD are crossed about the Corner of B is equal in a point 40 degrees And 80 degrees Find a-degree measure of a corner of C

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1) it is empty ugl And = x, ugl In = x / 2, ugl With = the 3rd

2) then we receive the equation -

x + x / 2+3Õ =180 (we multiply the equation by 2) (the sum of corners of a triangle)

of the 2nd + x the +6th =360

of the 9th =360

x =40

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Answer add