CBSE Class 9 - Maths - Quadrilaterals (NCERT Ex 8.2)

Quadrilaterals

NCERT Ex 8.2


Q1: ABCD is a quadrilateral in which P, Q, R and S are mid-points of the sides AB, BC, CD and DA (see the given figure). AC is a diagonal. Show that:



(i) SR || AC and SR = AC

(ii)PQ = SR

(iii)PQRS is a parallelogram.

Answer:

(i) In ▲ADC, S and R are the mid-points of sides AD and CD respectively.

In a triangle, the line segment joining the mid-points of any two sides of the triangle is parallel to the third side and is half of it.

∴ SR || AC and SR = AC ... (1)

(ii) In ▲ABC, P and Q are mid-points of sides AB and BC respectively. Therefore, by using mid-point theorem,

PQ || AC and PQ = AC ... (2)

Using equations (1) and (2), we obtain

PQ || SR and PQ = SR ... (3)

⇒ PQ = SR

(iii) From equation (3), we obtained

PQ || SR and PQ = SR

Clearly, one pair of opposite sides of quadrilateral PQRS is parallel and equal.

Hence, PQRS is a parallelogram.


Q2: ABCD is a rhombus and P, Q, R and S are the mid-points of the sides AB, BC, CD and DA respectively. Show that the quadrilateral PQRS is a rectangle.

Answer:

In ▲ABC, P and Q are the mid-points of sides AB and BC respectively.

∴ PQ || AC and PQ = AC (Using mid-point theorem) ... (1)

CBSE Class 9 - Science - CH4 - Gist on Structure of The Atom

Structure of The Atom

Study Points

1. Democritus, Greek Philosopher in 400 BC named the smallest piece of matter “ATOMOS ,” meaning “not to be cut.”
2. Dalton's theory (1803) was based on the premise that the atoms of different elements could be distinguished by differences in their weights.
3. WIth the invention of Scanning Tunneling Microscope we can see atoms.
4. Electrons, protons and neutrons are the fundamental particles of an atom.
5. Electrons were discovered by JJ Thomson in discharge tube experiments as cathode rays.
6. Cathode rays are streams of negatively charged particles.
7. They are deflected by electric and magnetic fields.
8. The specific charge of electron was determined by J. J. Thomson
9. The charge of the electron is 1.602 x 10-19 coulombs.
10. The absolute mass of electron is 9.108 x 10-28 g or 9.108 x 10-31kg
11. Protons are positive rays that were discovered by Goldstein in the discharge tube experiments when perforated metal cathode was used.

CBSE Class 11 - 12 English Grammar - Official Sentences

Official Sentences

Following sentences or phrases are commonly used for official or administrative work.

1. Arrangements are being made to ensure timely submission of reports.
2. Administrative approval may be obtained.
3. Competent authority's sanction is necessary.
4. Concurrence of the finance branch is necessary.
5. Exigencies of administrative work.
6. Explanation from the defaulter may be obtained.
7. His request be acceded to.
8. In anticipation of your approval.
9. Such action may be deemed necessary.
10. Repugnant to the context.
11. Show cause as to why such action should not be taken.
12. The file in question is not traceable.
13. Timely compliance may be ensured.

CBSE Class 7 - Science - CH3 - Fibre to Fabric (MCQs)

 Fibre to Fabric 

(MCQs)

Q1: Which of the following is NOT a Vegetable fibre?

(a) flax
(b) silk
(c) hemp
(d) jute

Q2: Vegetable fibres are made up of

(a) cellulose
(b) protein
(c) nylon
(d) rayon

Q3: Animal Fibres are made up of

(a) cellulose
(b) protein
(c) nylon
(d) rayon


Q4:  Which of the following process is NOT part of wool extraction?

CBSE Class 7 - Our Pasts - II -Ch 4 - The Creation of an Empire - TheMughal Dynasty (#eduvictors)(#Class7History)

The Creation of an Empire - 

The Mughal Dynasty

NCERT Textbook Solutions and Q & A

Taj Mahal
credits:openclipart

Q1: Match the following:

1. Mansab	(a) Marwar
2. Mongol	(b) Governor
3. Sisodiya Rajput	(c) Uzbeg
4. Rathor Rajput	(d) Mewar
5. Nur Jahan	(e) Babur
6. Subadar	(f) Rank

Answer:
1. Mansab - (f) Rank
2. Mongol - (c) Uzbeg
3. Sisodiya Rajput - (d) Mewar
4. Rathor Rajput - (a) Marwar
5. Nur Jahan - (e) Babur
6. Subadar - (b) governor


Q2: Fill in the blanks.

(a) The capital of Mirza Hakim, Akbar's Half brother, was __________
(b) The five Deccan Sultanates were Berar, Khandesh, Ahmadnagar, ___________ and ___________.
(c) If zat determined a mansabdar’s rank and salary, sawar indicated his ____________ .
(d) Abul Fazl, Akbar’s friend and counsellor, helped him frame the idea of ____________________ so that he could govern a society composed of many religions, cultures and castes.

Answer: (a) Kabul
(b) Bijapur, Golconda
(c) Cavalrymen
(d) Sulh-i-kul (or universal peace)


Q3: What were the central provinces under the control of the Mughals?

Answer: The central provinces under the control of the Mughals were:

• Lahore,
• Panipat,
• Delhi,
  
• Agra,
  
• Mathura,
  
• Amber,
  
• Ajmer,
  
• Fatehpur Sikri,
  
• Chittor,
• Ranthambhore and
  
• Allahabad.
  

Q4: What was the relationship between the mansabdar and the jagir?

CBSE Class 10 - KVS - SA1 - English- Question Paper-2012-13

CBSE Class 10 - KVS - SA1 - English- Question Paper-2012-13 

CBSE Class 10 - Social Science - SA1 - Sample Question Paper - 2014-15

Social Science - SA1 - Sample Question Paper - 2014-15

CLASS X

SOCIAL SCIENCE

SUMMATIVE ASSESSMENT I

Time: 3Hrs		Max. Marks: 90
	General Instructions:
1.	The question paper has 31 questions in all. All questions are compulsory.
2.	Marks are indicated against each question
3.	Questions from serial number 1 to 10 are multiple chouce questions (MCQs). Each question carries one mark.
4.	Questions from serial number 11 to 22 are 3 marks questions. Answer of these questions should not exceed 80 words each.
5.	Questions from serial number 23 to 30 are 5 marks questions. Answer of these questions should not exceed 100 words each.
6.	Question number 31 is a map question of 4 marks from Geography only. After completion attach map inside your answer book.
1	In which of the following years Great Depression occurred in the world? (a) 1929 - 30 (b) 1935 - 36 (c) 1939 - 40 (d) 1941 - 42
	OR
	Who among the following improved the steam engine produced by New Comen? (a) Mathew Boulton (b) James Watt (c) Henry Ford (d) Graham Bell
	OR
	Which one of the following is correct about the Annual London Season? (a) It was meant for wealthy Brishers only. (b) Organised for the working class. (c) Organised for the exchange of news. (d) Organised for political action.	(1)
2.	Which one of the following groups of the countries was known as the 'Central powers' in Europe? (a) Germany, Russia and France (b) Russia, Germany and Britain (c) Germany, Austria-Hungary and Ottoman-Turkey (d) Britain, Germany and Russia
	OR
	Which of the following group of industries were the dynamic industries of England during its earliest phase of industrialization? (a) Cotton and Metals (b) Cotton and Silk (c) Silk and Footwears (d) Footwears and glass
	OR
	After reclamation how many islands were joined together to develop the sity of Bombay (Mumbai)? (a) Seven (b) Five (c) Three (d) Ten	(1)
3.	Which one of the following soil types is the most widely spread and important soil in India? (a) Laterite soilds (b) Black soilds (c) Alluvial soilds (d) Red and yellow soils	(1)
4.	On which of the following rivers Sardar Sarvovar Dam is built? (a) River Kaveri (b) River Krishna (c) River Narmada (d) River Satluj	(1)
5.	Which of the following minority communites is relatively rich and powerful in Belgium? (a) French (b) Dutch (c) German (d) English