**Class 6 Mathematics Chapter 5 |**

**Understanding Elementary Shapes**** ****| Exercise 5.1**

1. What is the disadvantage in comparing line segments by mere observation?

**Answer**: The disadvantage in comparing line segments by mere observation is 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 of length or positioning error may occur. However divider gives up accurate measurement.

3. Draw any line segment, say A̅B̅, . 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, then we can be sure that C lies between A and B.]

**Answer: **

AB = 6.5 cm

AC = 3cm

CB = 3.5 cm

AC + CB = 3 cm + 3.5 cm

AB = 6.5 cm

4. If A,B,C are three points on a line such that AB = 5 cm, BC = 3 cm and AC = 8 cm, which one of them lies between the other two?

**Answer:**

AB = 5 cm,

BC = 3 cm and AC = 8 cm

AC = AB + BC

Point B is lying between A and C

5**.** Verify, whether D is the mid point of A̅G̅ ?

**Answer**: AD = 3 units

DB= 3 units

AG= 6 units

D is the mid point of AG.

6. If B is the mid point of A̅C̅ and C is the mid point of B̅D̅ , where A,B,C,D lie on a straight line, say why AB = CD?

**Answer**: B is the mid point of AC

∴ AB= BC ————(1)

And C is the mid-point of BD

BC= CD ————–(2)

From the equation we get,

AB = CD

7. Draw five triangles and measure their sides. Check in each case, if 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.

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