NCERT Solutions
Class 10 - Mathematics - Chapter 6: TRIANGLES
Exercise 6.2

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Question. 1

In Fig. 6.17, (i) and (ii), DE \(\parallel\) BC. Find EC in (i) and AD in (ii).

Answer:

(i) \(2\ \text{cm}\)

(ii) \(2.4\ \text{cm}\)

Question. 2

E and F are points on the sides PQ and PR respectively of a \(\triangle PQR\). For each of the following cases, state whether \(EF \parallel QR\):

  1. PE = 3.9 cm, EQ = 3 cm, PF = 3.6 cm and FR = 2.4 cm
  2. PE = 4 cm, QE = 4.5 cm, PF = 8 cm and RF = 9 cm
  3. PQ = 1.28 cm, PR = 2.56 cm, PE = 0.18 cm and PF = 0.36 cm

Answer:

(i) No

(ii) Yes

(iii) Yes

Question. 3

In Fig. 6.18, if LM \(\parallel\) CB and LN \(\parallel\) CD, prove that

\[\frac{AM}{AB} = \frac{AN}{AD}.\]

Answer:

\(\dfrac{AM}{AB} = \dfrac{AN}{AD}\)

Question. 4

In Fig. 6.19, DE \(\parallel\) AC and DF \(\parallel\) AE. Prove that

\[\frac{BF}{FE} = \frac{BE}{EC}.\]

Answer:

\(\dfrac{BF}{FE} = \dfrac{BE}{EC}\)

Question. 5

In Fig. 6.20, DE \(\parallel\) OQ and DF \(\parallel\) OR. Show that \(EF \parallel QR\).

Answer:

\(EF \parallel QR\)

Question. 6

In Fig. 6.21, A, B and C are points on OP, OQ and OR respectively such that AB \(\parallel\) PQ and AC \(\parallel\) PR. Show that BC \(\parallel\) QR.

Answer:

\(BC \parallel QR\)

Question. 7

Using Theorem 6.1, prove that a line drawn through the mid-point of one side of a triangle parallel to another side bisects the third side. (Recall that you have proved it in Class IX).

Answer:

A line drawn through the mid-point of one side of a triangle and parallel to another side bisects the third side.

Question. 8

Using Theorem 6.2, prove that the line joining the mid-points of any two sides of a triangle is parallel to the third side. (Recall that you have done it in Class IX).

Answer:

The line joining the mid-points of any two sides of a triangle is parallel to the third side.

Question. 9

ABCD is a trapezium in which AB \(\parallel\) DC and its diagonals intersect each other at the point O. Show that

\[\frac{AO}{BO} = \frac{CO}{DO}.\]

Answer:

Through O, draw a line parallel to DC, intersecting AD and BC at E and F respectively.

Question. 10

The diagonals of a quadrilateral ABCD intersect each other at the point O such that

\[\frac{AO}{BO} = \frac{CO}{DO}.\]

Show that ABCD is a trapezium.

Answer:

ABCD is a trapezium with \(AB \parallel CD\).

Disclaimer:The solutions provided here are prepared independently for educational purposes only. This material is not an official NCERT publication.
NCERT Solutions Class 10 – Mathematics – Chapter 6: TRIANGLES – Exercise 6.2 | Detailed Answers