CBSE > Class 09 > Mathematics | CBSE Board | Homework Help

1. Sum of all (15)nos = 15 *42 =630 2. Sum of 1st 8 nos = 40*8 = 320 3 Sum of last 8 nos = 44*8 = 352 Now, (try to understand properly)(think hard) let the 1st no be 'a' 2nd no be 'b' ........and so on. Then, 1st 8 nos will be a,b,c,d,e,f,g and h And Last 8 nos will be h,i,j,k,l,m,n and o *Thus, 8th observation is "h*". So, 15 nos - 1st 8 nos = last 8 nos - (h*) =>(a+b+c+d+e+f+g+h*+i+j+k+l+m+n+o)-(a+b+c+d+e+f+g+h*)=(h*+i+j+k+l+m+n+o)-(h*) => 630-320=352-h* =>630-320-352=-h* =>630-672=-h* =>-42=-h* =>h*= 42 So, 8th observation is 42. If you have any doubt, you can question me. Hope it helps!

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x - y = 180 find x, y

Posted by Rakshak Sharma 8 years, 3 months ago

CBSE > Class 09 > Mathematics

1 answers

Mridul Varshney 8 years, 3 months ago

X=360, y=180 x-y=180 360-170=180

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Is every irrational number s real nun

Posted by Vikas Rajput 8 years, 3 months ago

CBSE > Class 09 > Mathematics

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The total surface area of a right circular cone of slant height 13cm is 90 pai

Posted by Deep Lajpal 8 years, 3 months ago

CBSE > Class 09 > Mathematics

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What is an parallelogram

Posted by Kartik Bariya 8 years, 3 months ago

CBSE > Class 09 > Mathematics

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Ishan Bansal 8 years, 3 months ago

a parallelogram is a closed figure which is made up of 4 sides nd opposite sides are equal.

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An equilateral triangle whose side is a according to heron's formula do the questions what is an answer

Posted by Kartik Bariya 8 years, 3 months ago

CBSE > Class 09 > Mathematics

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An lateral triangle whose side is a according to heron's formula do the question

Posted by Kartik Bariya 8 years, 3 months ago

CBSE > Class 09 > Mathematics

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Represent 5 on number line

Posted by Anshul Yadav 8 years, 3 months ago

CBSE > Class 09 > Mathematics

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Proof that the radius passing through the mid point of chord is perpendicular to the chord

Posted by Riya Sharma 8 years, 3 months ago

CBSE > Class 09 > Mathematics

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If an angle of a parallelogram is two third of it's adjacent angle find the angle of the parallelogram.

Posted by Shristy Rai 8 years, 3 months ago

CBSE > Class 09 > Mathematics

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The surface area of the sphere is 154 sq.units . Then find it's volume?

Posted by Kartavya Kumar 8 years, 3 months ago

CBSE > Class 09 > Mathematics

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Nancy Garg 8 years, 3 months ago

178

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Maths chapter 13 exercise 13.4 sum no. 6 explain

Posted by Parth Joshi 8 years, 3 months ago

CBSE > Class 09 > Mathematics

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CPCT means

Posted by Syed Aj 8 years, 3 months ago

CBSE > Class 09 > Mathematics

3 answers

Aradhya Oberoy 8 years, 3 months ago

Corresponding part of congurent triangle

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Mridul Varshney 8 years, 3 months ago

Corresponding part of congruent triangle

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Piyush Gautam 8 years, 3 months ago

Corresponding parts of congruent triangle...

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Diagonal AC and BD of a trapezium ABCD with AB parallel DC intersect each other at O . Prove that area AOD=area BOC

Posted by Akshay Kumar Rai 8 years, 3 months ago

CBSE > Class 09 > Mathematics

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If all sides of a trapetrapezium is given then how we find its area

Posted by Apurv Gautam 8 years, 3 months ago

CBSE > Class 09 > Mathematics

2 answers

Ritik Singh 8 years, 3 months ago

1/2 sum of palleral side× difference between them

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Vishal Kaushik 8 years, 3 months ago

½(a + b) h.

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The surface area of a cuboid is 4212m2

Posted by Jeevan Benaka 8 years, 3 months ago

CBSE > Class 09 > Mathematics

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Theroum 10.1 solve

Posted by Ritik Singh 8 years, 3 months ago

CBSE > Class 09 > Mathematics

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What do you mean by math

Posted by Mohitnoor Singh 8 years, 3 months ago

CBSE > Class 09 > Mathematics

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Anshul Sharma 8 years, 3 months ago

Mathematics is the study of topics such as quantity (numbers), structure,space,and change.There are many views among mathematicians and philosophers as to the exact scope and definition of mathematics.

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Apurv Gautam 8 years, 3 months ago

Maths is another way to convey ans.

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(234)-(354)

Posted by Shristy Rai 8 years, 3 months ago

CBSE > Class 09 > Mathematics