Q3 of 29 Page 11

Co-ordinates of some pairs of points are given below. Hence find the distance between each pair.

i. 3, 6 ii. - 9, - 1


iii. - 4, 5 iv. x, - 2


v. x + 3, x – 3 vi. -25, - 47


vii. 80, - 85

The distance between the given pairs is as follows:

i. 3, 6


We know that 6 > 3, so


The required distance is 6 – 3 = 3.


ii. -9, -1


We know that -1 > -9, so


The required distance is -1 – (-9) = -1 + 9 = 8.


iii. -4, 5


We know that 5 > -4, so


The required distance is 5 – (-4) = 5 + 4 = 9.


iv. x, -2


Here, we consider two cases:


Case I When x > -2, then


The required distance is x – (-2) = x + 2.


Case II When -2 > x, then


The required distance is -2 – x.


More from this chapter

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1

Select the correct alternative from the answers of the question given below.

If P – Q – R and (P, Q) = 2, d(P,R) =10, then find d(Q, R).

 2

On a number line, co-ordinates of P, Q, R are 3, - 5 and 6 respectively. State with reason whether the following statements are true or false.

i. d(P,Q) + d(Q,R) = d(P,R)


ii. d(P,R) + d(R,Q) = d(P,Q)


iii. d(R,P) + d(P,Q) = d(R,Q)


iv. d(P,Q) - d(P,R) = d(Q,R)

 4

Co-ordinate of point P on a number line is - 7. Find the co-ordinates of points on the number line which are at a distance of 8 units from point P.

 5

Answer the following questions.

i. If A - B - C and d(A,C) = 17, d(B,C) = 6.5 then d (A,B) = ?


ii. If P - Q - R and d(P,Q) = 3.4, d(Q,R)= 5.7 then d(P,R) = ?