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qno2 ex 5.2 class 7 maths ncert || exercise 5.2 ncert class7 || corresponding angles
2. In the adjoining figure, identify
(i) the pairs of corresponding angles.
(ii) the pairs of alternate interior angles.
(iii) the pairs of interior angles on the same
side of the transversal.
(iv) the vertically opposite angles.
If two parallel lines are cut by a transversal, each pair of corresponding angles are
equal in measure.
If two parallel lines are cut by a transversal, each
pair of alternate interior angles are equal.
If two parallel lines are cut by a transversal, then each pair of interior angles on the same
side of the transversal are supplementary.


1. We recall that (i) A line-segment has two end points.
(ii) A ray has only one end point (its vertex); and
(iii) A line has no end points on either side.
2. An angle is formed when two lines (or rays or line-segments) meet.
Pairs of Angles Condition
Two complementary angles Measures add up to 90°
Two supplementary angles Measures add up to 180°
Two adjacent angles Have a common vertex and a common
arm but no common interior.
Linear pair Adjacent and supplementary
3. When two lines l and m meet, we say they intersect; the meeting point is called the
point of intersection.
When lines drawn on a sheet of paper do not meet, however far produced, we call
them to be parallel lines.
(i) (ii) (iii) (iv)
l m
112 MATHEMATICS
4. (i) When two lines intersect (looking like the letter X) we have two pairs of opposite
angles. They are called vertically opposite angles. They are equal in measure.
(ii) A transversal is a line that intersects two or more lines at distinct points.
(iii) A transversal gives rise to several types of angles.
(iv) In the figure, we have
Types of Angles Angles Shown
Interior ∠3, ∠4, ∠5, ∠6
Exterior ∠1, ∠2, ∠7, ∠8
Corresponding ∠1 and ∠5, ∠2 and ∠6,
∠3 and ∠7, ∠4 and ∠8
Alternate interior ∠3 and ∠6, ∠4 and ∠5
Alternate exterior ∠1 and ∠8, ∠2 and ∠7
Interior, on the same ∠3 and ∠5, ∠4 and ∠6
side of transversal
(v) When a transversal cuts two parallel lines, we have the following interesting
relationships:
Each pair of corresponding angles are equal.
∠1 = ∠5, ∠3 = ∠7, ∠2 = ∠6, ∠4 = ∠8
Each pair of alternate interior angles are equal.
∠3 = ∠6, ∠4 = ∠5
Each pair of interior angles on the same side of transversal are supplementary.
∠3 + ∠5 = 180°, ∠4 + ∠6 = 180°