When two lines intersect, they form two pairs of vertically opposite angles. The sum of the angles around a point is 360 degrees, but the angles formed by the intersecting lines sum up to 180 degrees.

When two lines intersect, they form two pairs of vertically opposite angles. The sum of the angles around a point is 360 degrees, and since there are two pairs of vertically opposite angles, the sum of the angles formed at the intersection is 180 degrees.

Alternate interior angles are equal when two parallel lines are cut by a transversal. Therefore, the other angle is also 45 degrees.

Alternate interior angles are equal when two parallel lines are cut by a transversal. Therefore, the other alternate interior angle is also 75 degrees.

When two parallel lines are cut by a transversal, the alternate interior angles are equal.

Alternate exterior angles are equal when two parallel lines are cut by a transversal. Therefore, if one angle is 120 degrees, the other alternate exterior angle is also 120 degrees.

Complementary angles sum up to 90 degrees. Therefore, the other angle = 90 - 30 = 60 degrees.

Adjacent angles on a straight line are supplementary. Therefore, the adjacent angle measures 180 - 35 = 145 degrees.

Supplementary angles sum up to 180 degrees. Therefore, the other angle is 180 - 110 = 70 degrees.

Vertically opposite angles are equal. Therefore, if one angle measures 120 degrees, the other angle also measures 120 degrees.

In a right triangle, the sum of the angles is 180 degrees. If one angle is 45 degrees and the right angle is 90 degrees, the other angle must be 180 - (90 + 45) = 45 degrees.

The sum of the angles in a triangle is always 180 degrees. Therefore, if two angles are 45 degrees each, the third angle = 180 - (45 + 45) = 90 degrees.

The sum of angles in a triangle is 180 degrees. Therefore, the third angle = 180 - (50 + 60) = 70 degrees.

The sum of angles in a triangle is 180 degrees. Therefore, the third angle = 180 - (40 + 70) = 70 degrees.

The sum of angles in a triangle is 180 degrees. Therefore, the third angle = 180 - (45 + 55) = 80 degrees.

The sum of angles in a triangle is 180 degrees. Therefore, the third angle = 180 - (50 + 60) = 70 degrees.

The sum of angles in a triangle is 180 degrees. Therefore, the third angle = 180 - (50 + 60) = 70 degrees.

The sum of angles in a triangle is 180 degrees. Therefore, the third angle = 180 - 60 - 80 = 40 degrees.

If two lines are perpendicular, the sum of their angles is 90 degrees. Therefore, if one line makes an angle of 30 degrees with the horizontal, the other line must make an angle of 90 - 30 = 60 degrees with the horizontal.

Perpendicular lines intersect at right angles, which measure 90 degrees.

Vertically opposite angles are equal. Therefore, the measure of the vertically opposite angle is also 70 degrees.

Vertically opposite angles are equal. Therefore, the measure of the vertically opposite angle is also 35 degrees.

Adjacent angles formed by intersecting lines are supplementary. Therefore, 180 - 70 = 110 degrees.

Alternate interior angles are equal when two parallel lines are cut by a transversal. Therefore, if one angle is 65 degrees, the other alternate interior angle is also 65 degrees.

Supplementary angles sum to 180 degrees. Therefore, the angle is 180 - 75 = 105 degrees.

Supplementary angles sum up to 180 degrees. Therefore, the angle measures 180 - 110 = 70 degrees.

The exterior angle of a triangle is equal to the sum of the two opposite interior angles. Therefore, the exterior angle = 50 + 60 = 110 degrees.

Complementary angles sum up to 90 degrees. If one angle is 30 degrees, the other angle is 90 - 30 = 60 degrees.

The measure of each interior angle in a regular hexagon can be calculated using the formula (n-2) * 180/n, where n is the number of sides. For a hexagon, n=6, so the measure is (6-2) * 180/6 = 120 degrees.

A regular quadrilateral is a square, and each angle in a square measures 90 degrees.