Ask a Doubt
Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 9 Answered

prove that the sum of angles of a triangle is 180.Using this find all the angles of a triangle if the angles are in the ratio 1:2:3.
Give your view how the measure of angles useful in making furniture?
Is accuracy necessary in measurements?
Asked by kumarasia | 22 Sep, 2014, 08:47: AM
answered-by-expert Expert Answer
C o n s i d e r space t h e space f o l l o w i n g space f i g u r e.
 
L e t space A B C space b e space a space t r i a n g l e. C o n s t r u c t i o n : D r a w space a space l i n e space P A Q space p a r a l l e l space t o space B C S i n c e space B C space i s space p a r a l l e l space t o space P Q comma space a n d space A B space i s space a space t r a n s v e r s a l comma space w e space h a v e comma angle P A B equals angle A B C... left parenthesis 1 right parenthesis S i n c e space B C space i s space p a r a l l e l space t o space P Q comma space a n d space B C space i s space a space t r a n s v e r s a l comma space w e space h a v e comma angle C A Q equals angle A C B... left parenthesis 2 right parenthesis S i n c e space P A Q space i s space a space s t r a i g h t space l i n e comma space w e space h a v e comma angle P A Q space i s space a space s t r a i g h t space a n g l e. rightwards double arrow angle P A Q equals angle P A B plus angle B A C plus angle C A Q equals 180 degree.... left parenthesis 3 right parenthesis S u b s t i t u t i n g space t h e space v a l u e s space o f space angle P A B space a n d space angle C A Q space f r o m space e q u a t i o n s space left parenthesis 1 right parenthesis space a n d space left parenthesis 2 right parenthesis space i n space e q u a t i o n space left parenthesis 3 right parenthesis comma space w e space h a v e comma angle A B C plus angle B A C plus angle A C B equals 180 degree. H e n c e space t h e space a n g l e space s u m space p r o p e r t y space i s space p r o v e d.
G i v e n space t h a t space t h e space a n g l e s space o f space a space t r i a n g l e space a r e space i n space t h e space r a t i o space 1 : 2 : 3 T h a t space i s space t h e space a n g l e s space a r e space x comma space 2 x space a n d space 3 x. B y space a n g l e space s u m space p r o p e r t y comma space x plus 2 x plus 3 x equals 180 degree rightwards double arrow 6 x equals 180 degree rightwards double arrow x equals fraction numerator 180 degree over denominator 6 end fraction rightwards double arrow x equals 30 degree T h u s space t h e space a n g l e s space a r e space 30 degree comma 60 degree space a n d space 90 degree
 
 
Answered by Vimala Ramamurthy | 22 Sep, 2014, 10:49: AM

Application Videos

Concept Videos

Multiple Choice Questions Practice Test
Answered Unanswered My Questions My Answers
CBSE 9 - Maths
Q12.
question image
Asked by UTKARSH.CHANDRA.02008 | 09 Jul, 2022, 09:54: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
the exterior angles obtained on producing the base of a triangle both ways are 100° and 120°. find all the angles
Asked by raghavgargrg28 | 10 Sep, 2021, 05:11: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
how to remember all the thereoms
Asked by kamateganpati | 08 Sep, 2021, 06:17: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
In a triangle ABC, if  angle A + angle B = 65 and  angle B +  angle C = 140 , then the measure of  angle B is (a) 40 (b) 25 c) 115 (d) 60
Asked by swatipuspapatel | 07 Feb, 2021, 07:29: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
one exterior angle of a triangle is 110 degree and one ko interior opposite angle is 30 degree find the remaining angles of the triangle
Asked by sanjanatirthani0574 | 12 Sep, 2020, 10:18: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
What is angle sum property   
Asked by Tanushkadari456 | 22 Sep, 2019, 05:50: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
In the given figure, AB||CD. Find the value of x.
question image
Asked by Santosh.kumar0317 | 19 Aug, 2019, 05:12: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
answer to all question  
question image
Asked by Chetna.lagoon | 18 Aug, 2019, 07:32: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
Please answer this question 
question image
Asked by Girishdhawan | 01 Jul, 2018, 03:13: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Maths
Can a triangle have (i) Two right angles?     (ii) All angles less than 60o? (iii) All angles equal to 60o?  (iv)Two acute angles? Justify your statement in each case.
Asked by Topperlearning User | 04 Jun, 2014, 01:23: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
My Class Videos Tests ₹ Plans Ask a Doubt
Get Latest Study Material for Academic year 24-25 Click here
×