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Q. 4  4 Marks Each

A) Name all the angles formed in the figure given below

 

 



Name of All the angles in this figure are:
1) /_BAC
2) /_ABC
3) /_ACB
4) /_BDC
5) /_BOD
6)/_COD
7) /_BDO
8) /_CDO
9)/_OCD
10)/_OBD



B) Find 5/6 of 84
This example is a simple multiplication of a whole number with fraction:

5/6 x 84 = 5 x 14 = 60 Answer

C) Make factor tree of 30 in two different ways.

Method 1:
 2| 30
 3| 15
 5| 5
  |  1

Therefore factor of 30 are: 1, 2, 3, 5, 6, 15 and 30

See course material of 6 th standard where i have shown how to find factors of a given number.

Second method could be prime factorization method but in that method you only get prime numbers as factors.

Ask the teacher for second method to find factors

D) Find the HCF by using division method 64 and 80


2|  64    80
2|  32    40
2|  16    20
2|  8     10
  | 4      5

Thus HCF = 2 x 2 x 2 x 2  = 16 is the Answer

There is other method to determine HCF using Prime factorization Method

Solve 64 and 80 separately

2| 64
2 | 32
2| 16
2 | 8
2|4
2|2
 | 1

So prime factors are: 2 x 2 x 2 x 2 x 2 x 2

Solve 80:

2| 80
2 | 40
2 | 20
2| 10
5| 5
  | 1

So prime factors are 2 x 2 x 2 x 2 x 5

Here common factors in two numbers are 4 2's i.e. 2 x 2 x 2 x 2 = 16. This answer matches the answer obtained above.



E) Write in  ascending order


2/3, 2/5, 2/7, 2/1


Since the numerator is constant; the fraction is greater if the denominator is smaller.
Therefore 2/7 is smallest, 2/5 is greater, 2/3 is still greater, 2/1 is the greatest hence the ascending order