# Line and Angle Important Questions

Given below are the Class 9 Maths Important Questions for Geometry
• Concepts questions
• Calculation problems
• Multiple choice questions
• Fill in the blanks

Question 1
Write the type of angles

Solution
a. Acute angle
b. Right angle
c. Obtuse angle
d. Straight angle
e. Reflex angle
f. Vertically opposite angle
g. Alternate interior angles

Question 2
True or False statement
a. Pairs of vertically opposite angles is always equal
b. The sum of the angles of a triangle is $180^0$
c. If the sum of two adjacent angles is $45^0$, then two adjacent angles are acute angles
d. If a line is perpendicular is one of two parallel lines, then it is also perpendicular to the other
e. Two lines are intersected by the transversal, and then the corresponding angles are equal
f. Can we have a triangle where all the interior angles are more than $60^0$
g. Sum of two complimentary angles is equal to $90^0$
h. Sum of all the exterior angles of any polygon is always $360^0$
Solution
• True
• True
• True
• True
• False
• False
• True
• True

## Multiple choice Questions

Question 3
Find the value of x

a. $98^0$
b. $100^0$
c. $108^0$
d. $96^0$
Solution
(c)
$x+36+36=180$ => $x=108^0$

Question 4
A pair of angles is called linear pair if the sum of two adjacent angles is?
a.$180^0$
b.$90^0$
c.$270^0$
d.$360^0$
Solution
(a)

Question 5
Find the value of x,y and z

a. $x=110^0,y=70^0,z=80^0$
b. $x=70^0,y=110^0,z=60^0$
c. $x=70^0,y=100^0,z=70^0$
d. $x=70^0,y=110^0,z=70^0$
Solution
(d)
Vertically opposite angle theorem and linear pair axiom can be used to find the answer

Question 6
An exterior angle of the triangle is $110^0$. And its two opposite interior angles are in the ratio 5:6. What are the values of those angles?
a. $50^0,60^0$
b. $25^0,30^0$
c. $35^0,42^0$
d. $40^0,48^0$
Solution (a)

Question 7
Lines l || k and m || n .Find the value of angle z

a. $45^0$
b. $60^0$
c. $70^0$
d. $50^0$
Solution (b)

Question 8

Find the value of x
a. $67^0$
b. $71^0$
c. $57^0$
d. None of these
Solution (a)

## Fill in the blanks

Question 9
a.Sum of two supplementary angles is ______
b. Two lines parallel to the same line is ____ each other
c. An acute angle is always less than _____
d. Angles forming a linear pair are ______
e. If one angle of triangle is equal to the sum of other two angles, then the triangle is ______
f. if two straight lines intersect ,the adjacent angles are ______
Solutions
a. $180^0$
b. parallel
c. $90^0$
d. supplementary
e. right angle triangle
f. Supplementary

## Table Type Question

Question 9
 Angle $30^0$ $80^0$ $11^0$ $87^0$ Complementary angle Supplementary angle
Solution:
Complementary =$90- x$
Supplementary =$180 -x$

• Notes
• Assignments

Reference Books for class 9 Math

Given below are the links of some of the reference books for class 9 Math.

1. Mathematics for Class 9 by R D Sharma One of the best book for studying class 9 level mathematics. It has lot of problems to be solved.
2. Secondary School Mathematics for Class 9 by R S Aggarwal This is also as good as R.D. Sharma. Either this or the book by R.D. Sharma will do. I find book R.S. Aggarwal little bit more challenging than the one by R.D. Sharma.
3. Pearson IIT Foundation Series - Maths - Class 9 Buy this book if you want to challenge yourself further and want to prepare for JEE foundation.
4. Pearson IIT Foundation Physics, Chemistry & Maths combo for Class 9 Only buy if you are prepared to study extra topics and want to take your studies a step further. You might need help to understand topics in these books.

You can use above books for extra knowledge and practicing different questions.

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