Class 7 Maths Lines And Angles | Important Questions For Exam

IMPORTANT QUESTIONS FOR CBSE EXAMINATION | CLASS 7 MATHEMATICS
LINES AND ANGLES – Chapter 5

Answer the following (2 marks):

1. Classify the given angles as acute, obtuse, straight angle, right angle.
34, 120, 76, 180, 90, 2 x 90, 69, 165, 92

2. Write the supplement of the following angles:

a) 45
b) 90

3. Write the complement of the following angles:

a) 25
b) 65

4. Identify which of the following pairs of angles are complementary and which are supplementary.

a) 60, 120
b) 60, 30
c) 110, 70
d) 45, 45
e) 70, 20

5. Find the values of the angles x, y and z in each of the following:

7. In the adjoining figure, identify the following:
a) Pair of corresponding angles
b) Pairs of alternate interior angles
c) Pair of vertically opposite angles.
d) Pair of interior angles on the same side of the transversal.

ANSWERS:

1. Acute angles – 34, 76, 69

Obtuse angles – 120, 165, 92
Straight angles – 180, 2 x 90
Right angle – 90

2. When the sum of the measure of two angles is 180 degree, the angles are called supplementary angles.

a) 180 – 45 = 135
b) 180 – 90 = 90

3. When the sum of the measures of two angles is 90 degree, the angles are called complementary angles.

a) 90 – 25 = 65
b) 90 – 65 = 25

4. Complementary angles – 60, 30 / 45, 45 / 70, 20.

Supplementary angles – 60, 120 / 110, 70

5. z = 115 (vertically opposite angles)

x = 180 – 115 = 65 (linear pair)
y = 65 (vertically opposite angles)

6. x = 180 – 150 = 30 (linear pair)

y = 180 – (80 + 30) = 180 – 110 = 70 (angle sum property)
z = 70 (alternate angles are equal)

7. a) Corresponding angles are <1, <5 / <2, <6 / <3, <7/ <4, <8
b) Alternate interior angles are <3, <6 / <4, <5
c) Vertically opposite angles are <1, <4/ <2, <3/ <5, <8/ <7, <6
d) Interior angles on the same side of the transversal are <3, <5 and <4, <6.