Maharashtra State BoardSSC (English Medium) 7th Standard

In the Right-angled ∆Lmn, ∠M = 90°. If L(Lm) = 12 Cm and L(Ln) = 20 Cm, Find the Length of Seg Mn. - Mathematics

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Sum

In the right-angled ∆LMN, ∠M = 90°. If l(LM) = 12 cm and l(LN) = 20 cm, find the length of seg MN.

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Solution

In the right-angled triangle LMN, ∠M = 90°. Hence, side LN is the hypotenuse.
According to Pythagoras' theorem,
l(LN)2 = l(MN)2 + l(LM)2
⇒ (20)2 = l(MN)2 + (12)2
⇒ 400 = l(MN)2 + 144
⇒ l(MN)2 = 400 − 144
⇒ l(MN)2 = 256
⇒ l(MN)2 = (16)2
⇒ l(MN) = 16
∴ Length of seg MN = 16 cm.

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Chapter 13: Pythagoras’ Theorem - Practice Set 48 [Page 90]

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Balbharati Mathematics 7th Standard Maharashtra State Board
Chapter 13 Pythagoras’ Theorem
Practice Set 48 | Q 3 | Page 90

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