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Find the perimeter of the rectangle whose length is 40 cm and a diagonal is 41 cm. - Mathematics

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Question

Find the perimeter of the rectangle whose length is 40 cm and a diagonal is 41 cm.

Sum
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Solution

Length of rectangle = 40 cm, Diagonal = 41 cm

Let the breadth of rectangle = x cm

From right angled triangle ΔABC,

AC2 = AB2 + BC2

(41)2 = (40)2 + BC2

BC2 = 1681 – 1600

BC2 = 81

BC = 9

Perimeter of rectangle = 2 (40 + 9)

= 2 × 49

= 98 cm

Hence, perimeter of rectangle = 98 cm

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Chapter 6: The Triangle and its Properties - Exercise 6.5 [Page 130]

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NCERT Mathematics [English] Class 7
Chapter 6 The Triangle and its Properties
Exercise 6.5 | Q 7 | Page 130

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