# NCERT Class 7 Mathematics Solutions: Chapter 7 –Congruence of Triangles Exercise 7.2 Part 4

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1. In a squared sheet, draw two triangles of equal area such that:

(i) The triangles are congruent.

(ii) The triangles are not congruent.

What can you say about their perimeters?

Answer:

In a squared sheet, draw .

When two triangles have equal areas and

(i) These triangles are congruent, i.e., [By SSS congruence rule]

Then, their perimeters are same because length of sides of first triangle are equal to the length of sides of another triangle by SSS congruence rule.

(ii) But, if the triangles are not congruent, then their perimeters are not same

Because lengths of sides of first triangle are not equal to the length of corresponding sides of another triangle.

2. Draw a rough sketch of two triangles such that they have five pairs of congruent parts but still the triangles are not congruent.

Answer:

Consider,

Draw two triangles PQR and ABC.

All angles are equal; two sides are equal except one side.

So, are not congruent to .

3. If and are to be congruent, name one additional pair of corresponding parts. What criterion did you use?

Answer:

are congruent.

The one additional pair is

So, [By ASA congruence rule]