# Parallel Lines

The lines that do not intersect each other are called**Parallel lines.**

**Example**: Railway tracks,lines on the note book etc.

**Transversal :**The line which cuts the two parallel-lines in two distinct points is called

**transversal.**

The eight angles are formed by parallel-lines and transversal , they are

**Types of Angles made by Transversal with two Lines**

1) Corresponding angles : There are 4 pairs of corresponding angles.

These angles are formed on letter

**“F"**.

If the lines are parallel then the measures of corresponding angles are equal.

Corresponding Angles∠a = ∠e ∠d = ∠h ∠b = ∠f ∠c = ∠g |

2)Alternate interior angles : There are 2 pairs of alternate interior angles.

These angles are formed on letter

**“z"**.

If the lines are parallel then the measures of alternate interior angles are equal.

Alternate Interior Angles∠d = ∠f ∠c = ∠e |

3)Interior angles on the same side of transversal : There are two pairs of interior angles.

These angles are formed on letter

**“C"**.

If the lines are parallel then the interior angles on the same side of transversal are supplementary.( sum up to 180)

Interior Angles∠a + ∠b = 180 ^{0}∠c + ∠d = 180 ^{0} |

4) Alternate exterior angles : There are two pairs of alternate exterior angles.

Alternate Exterior Angles∠a = ∠g ∠b = ∠h |

If the lines are parallel then the measures of alternate exterior angles are equal.

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**Practice**

Use the following figure and answer the given questions:

1) State all the corresponding angles.

2) Give the names of alternate interior angles.

3) If m∠b = 40

^{0}then find the remaining angles and state the reasons for it.

**Basic Geometry**

• Point

• Lines

• Angles

• Lines and Angles

• Complementary angles

• Supplementary angles

• Vertically Opposite Angles

• Linear Pair Angles

• Adjacent Angles

• Parallel Lines

• Solved Problems on Intersecting Lines

• Solved Problems on Parallel Lines

• Point

• Lines

• Angles

• Lines and Angles

• Complementary angles

• Supplementary angles

• Vertically Opposite Angles

• Linear Pair Angles

• Adjacent Angles

• Parallel Lines

• Solved Problems on Intersecting Lines

• Solved Problems on Parallel Lines