answersLogoWhite

0

_\_________

.a\b

_c\d________

.....\

When a line crosses 2 lines, 8 angles are formed.

Four are exterior angles - outside the 2 lines, and four are interior angles.

These are labelled a, b, c, d in the diagram.

a & d are alternate interior angles because they alternate from one side

of the intersecting line to the other; b & c are also alternate interior angles.

They are also known as "Z-angles" because the top parallel line, the transversal and the bottom parallel line which define the two angles for the letter Z (or a distorted version of it).

If angle a = angle d (in which case angle b = angle c as well), the 2 lines drawn horizontally are parallel.

If alternate interior angles are equal, the 2 lines are parallel.

OR If you know the lines are parallel, then alternate interior angles must be equal.

Not the greatest diagram; please ignore the ... but even a lousy diagram helps.

And no, you don't use lower case letters for angles but there shouldn't be any confusion.

User Avatar

Wiki User

12y ago

What else can I help you with?

Continue Learning about Natural Sciences

Alternate interior angle theorem?

The alternate interior angle theorem states that when two parallel lines are cut by a transversal, the alternate interior angles formed are congruent. In other words, if two parallel lines are crossed by a third line, then the pairs of alternate interior angles are equal in measure.


What are angles that share a vertex and a side of a transversal but no interior points?

The angles that share a vertex and a side of a transversal but no interior points are called vertical angles. Vertical angles are formed when two lines intersect, and they are always congruent.


What are exterior angles?

Exterior angles are the angles formed when a side of a polygon is extended, and they are adjacent to the interior angle at that vertex. In a polygon with n sides, there are n exterior angles, one at each vertex. The sum of the exterior angles of any polygon is always 360 degrees.


What is the formula for icosagon?

For a regular icosagon (20-sided polygon), the formula to calculate the sum of its interior angles is (n-2) * 180 degrees, where n is the number of sides. So, for an icosagon, the sum of its interior angles can be calculated as (20-2) * 180 = 3240 degrees.


How does the lone pair contribute to molecule shape?

The lone pair on an atom exerts repulsion on bonded pairs of electrons, which can distort the bond angles and contribute to the overall shape of the molecule. In some cases, the presence of a lone pair can cause a deviation from the expected bond angles in a molecule, leading to a specific geometry such as trigonal pyramidal or bent.

Related Questions

Are the alternate interior angles of two parallel lines cut by a transveral always interior?

Yes. "Alternate interior" angles are always interior. Angles that are not interior as well as alternate are never accurately described as "alternate interior" angles.


What are two pairs of alternate interior angles?

They are 4 alternate interior angles.


Alternate interior angle theorem?

The alternate interior angle theorem states that when two parallel lines are cut by a transversal, the alternate interior angles formed are congruent. In other words, if two parallel lines are crossed by a third line, then the pairs of alternate interior angles are equal in measure.


Are alternate angles congruent?

Yes. Alternate interior and alternate exterior angles are congruent.


What types of angles are equal?

alternate interior and alternate exterior angles


What is a pair of angles that lie between the parallel lines on opposite sides of the transversal?

Those are "alternate interior" angles. They're always equal.


What is meant by alternate Interior angles?

Alternate interior angles are equal on a transversal that passes through parallel lines.


Why are alternate interior angles and alternate exterior angles both called alternate?

Both alternate interior and alternate exterior angle pairs lie on opposite sides of the transversal.


Two interior angles on opposite sides of a transversal?

Alternate interior angles.


What is special about the angles in a pair of alternate angles?

They are equal.


Nonadjacent interior angles that lie on opposite sides of the transversal?

Alternate Interior Angles


Parallel lines form congruent alternate interior angles?

Parallel lines cut by a transversal form congruent alternate interior angles.