Identifying Line Segments and Angles

A line segment is a part of a line that has two endpoints.

An angle is formed when two lines or line segments meet at a point.

The starting point of a ray is called its origin and is denoted by 'O' .

A line has infinitely many end points.

When you extend the two endpoints of a line segment in either direction endlessly, you get a line.

The corners formed when two lines or line segments intersect at a point are called angles.

In Fig 5.3 (i), the angles formed by line segments AB and BC are ∠ABC, ∠BCA, and ∠BAC.

In Fig 5.3 (ii), the four angles formed by lines PQ and RS are represented as ∠POS, ∠SOQ, ∠QOR, and ∠ROP.

Two angles are complementary if the sum of their measures is 90°.

No, two acute angles cannot be complementary to each other.

The measure of the complement of a 45º angle is 45º.

If the difference in the measures of two complementary angles is 12°, the measures of the angles are 51° and 39°.

Yes, two obtuse angles can be supplementary to each other.

The measure of the supplement of a 100º angle is 80º.

In two supplementary angles, the measure of the larger angle is 44° greater than the smaller angle.

In Fig 5.5, angles (i) and (iii) are complementary.

PQ is the symbol generally used to denote a line segment.

Corners formed when two lines or line segments intersect at a point are called angles.

When you extend the two endpoints of a line segment in either direction endlessly, you get a line.

The starting point of a ray is denoted by 'O'.

Angles are formed when lines or line segments meet at a point.

A ray is generally denoted by OP.

No, two obtuse angles cannot be complementary to each other.

No, two acute angles cannot be complementary to each other.

No, two right angles cannot be complementary to each other.

The measure of the complement of a 45º angle is 45º.

The measure of the complement of a 65º angle is 25º.

The measure of the complement of a 41º angle is 49º.

The measure of the complement of a 54º angle is 36º.

Yes, two obtuse angles can be supplementary to each other.

No, two acute angles cannot be supplementary to each other.

No, two right angles cannot be supplementary to each other.