Class 6 - Mathematics : Understanding Elementary
Exercise : 5.1
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NCERT Solutions Class 6 Mathematics Understanding Elementary Ex 5.1
1.What is the disadvantage in comparing line segments by mere observation?
Answer :
There may be chance of error due to improper viewing.
2.Why is it better to use a divider than a ruler, while measuring the length of a line segment?
Answer :
It is better to use a divider than a ruler, because the thickness of the ruler may cause difficulties in reading off her length. However divider gives up accurate measurement.
3.Draw any line segment, say AB. Take any point C lying in between A and B. Measure the lengths of AB, BC and AC. Is AB = AC + CB?
[Note: If A, B, C are any three points on a line, such that AC + CB = AB, hence we can be sure that C lies between A and B.]
Answer :
Yes.
AB = 6.5 cm, AC = 3cm, CB = 3.5 cm
AC + CB = 3 cm + 3.5 cm = 6.5 cm = AB
4.If A, B, C are three points on a line such that AB = 5 cm, BC = 3cm and AC = 8 cm, which one of them lies between the other two?
Answer :
AC is the longest line segment, thus B is the point between A and C.
5.Verify whether D is the mid-point of AG.
Answer :
AD = 3 units, DG = 3 units
AD = DG.
Thus, D is the mid-point.
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6. If B is the mid-point of AC and C is the mid-point of BD, where A, B, C, D lie on a straight line, say why AB = CD?
Answer :
B is the mid-point of AC.
∴ AB = BC ……….(i)
And C is the mid-point of BD.
∴ BC = CD ……….(ii)
From eq. (i) and (ii),
AB = CD
7.Draw five triangles and measure their sides. Check in each case, of the sum of the lengths of any two sides is always less than the third side.
Answer :
Yes, sum of two sides of a triangle is always greater than the third side.