CBSE NCERT Solutions for Class 7 Chapter 7

NCERT Solutions for Class 7 is a very important resource for students of CBSE Class 7. Answers have been prepared in a logical and simple language for fast revisions during examination. This also provides important points to remember after every chapter with the complete summary, important formulas and well-illustrated examples covering all the topics in the textbooks.

CBSE NCERT Solutions for Class 7 Maths Chapter 7:

Question-1:

In ABC, A = 30○, B = 40 and C = 110.
In PQR, P = 30○,Q = 40 and R = 110.
A student says that ABC≅ PQR by AAA congruence criterion. Is he justified? Why or why not?

Solution:

No, because the two triangles with equal corresponding angles need not be congruent. In such a correspondence, one of them can be an enlarged copy of the other.

Question-2:

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?

Solution:

In a squared sheet, draw triangle ABC and triangle PQR.
When two triangles have equal areas and
(i) These triangles are congruent, i.e., ABC ≅ PQR [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.

Question-3:

Complete the following statements:
(a) Two line segments are congruent if
(b) Among two congruent angles one has a measure of 70,the measure of other angle is (c) When we write A = B, we actually mean

Solution:

They have the same length.
70
m <A = m <B

Question-4:

Give any two real time examples for congruent shapes.

Solution:

(i) Two footballs
(ii) Two teacher ‘s tables