Answer: 30°
Explanation: so we know line F has to be 180° because it’s a line. it tells us the angle is 140°, so we know the interior angle is 40° because 180°-140°=40°. we also know that a triangle is 180°. so we have the two angles of the triangle: 110° and 40°. to find the third angle we find 110°+40°+?=180°. once we solve, we know the third angle is 30° because 180°-150°=30°.
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