What is the sum of the blue angles?

$270^\circ$
$360^\circ$
$180^\circ$
$90^\circ$

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The sum of the blue angles, is equal to the sum of the angles in the green triangles, minus the angle on the line. Hence, it is equal to

$2 \times 180^\circ - 180^ \circ = 180^ \circ$