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X and Y are points on the side LN of the triangle LMN such that LX = XY = YN. Through X, a line is drawn parallel to LM to meet MN at Z (See figure). Prove that ar (LZY) = ar (MZYX)

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Question

X and Y are points on the side LN of the triangle LMN such that LX = XY = YN. Through X, a line is drawn parallel to LM to meet MN at Z (See figure). Prove that ar (LZY) = ar (MZYX)

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Solution

Given: X and Y are points on the side LN such that LX = XY = YN and XZ || LM

To prove: ar (ΔLZY) = ar (MZYX)

Proof: Since, ΔXMZ and ΔXLZ are on the same base XZ and between the same parallel lines LM and XZ.

Then, ar (ΔXMZ) = ar (ΔXLZ)  ...(i)

On adding ar (ΔXYZ) both sides of equation (i), we get

ar (ΔXMZ) + ar (ΔXXZ) = ar (ΔXLZ) + ar (ΔXYZ)

⇒ ar (MZYX) = ar (ΔLZY)

Hence proved.

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Chapter 9: Areas of Parallelograms & Triangles - Exercise 9.3 [Page 90]

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NCERT Exemplar Mathematics Exemplar [English] Class 9
Chapter 9 Areas of Parallelograms & Triangles
Exercise 9.3 | Q 2. | Page 90

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