NCERT Solutions for Class 7 Mathematics Chapter 6
Important NCERT Questions
Class vii Math Chapter 6 The Triangles and Its Properties Exercise 6.5
NCERT Books for Session 2022-2023
CBSE Board
Questions No: 7
Find the perimeter of the rectangle whose length is 40 cm and a diagonal is 41 cm.
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Given diagonal (PR) = 41 cm, length (PQ) = 40 cm
Let breadth (QR) be x cm.
Now, in right angled triangle PQR,
(PR)² = (RQ)² + (PQ)² [By Pythagoras theorem]
⇒ (41)² = x² + 1600
⇒ 1681 = x² + 1600
⇒ x² = 1681 – 1600
⇒ x² = 81
⇒ x= √81 = 9 cm
Therefore the breadth of the rectangle is 9 cm.
Perimeter of rectangle = 2(length + breadth)
= 2 (9 + 49)
= 2 x 49 = 98 cm
Hence, the perimeter of the rectangle is 98 cm.
Class 7 Maths Chapter 6 Exercise 6.5
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https://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-6/