# Mathematics Class 6 NCERT Solutions: Chapter 5 Understanding Elementary Shapes Exercise 5.1

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

Answer: There may be chance of error due to improper viewing.

Q.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.

Q.3 Draw any line segment, say . Take any point C lying in between A and B. Measure the lengths of AB, BC and AC. Is ?

[Note: If A, B, C are any three points on a line, such that , then we can be sure that C lies between A and B.]

Q.4 If A, B, C are three points on a line such that , which one of them lies between the other two?

Answer: is the longest line segment, thus B is the point between A and C.

Q.5 Verify whether is the mid-point of.

Thus, D is the mid-point.

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

B is the mid-point of .

AB = BC ... (i)

And C is the mid-point of .

BC = CD ... (ii)

From equation (i) and (ii), we get

AB = CD

Q.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.