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The given figure shows a pentagon ABCDE. EG drawn parallel to DA meets BA produced at G and CF draw parallel to DB meets AB produced at F. - Mathematics

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Question

The given figure shows a pentagon ABCDE. EG drawn parallel to DA meets BA produced at G and CF draw parallel to DB meets AB produced at F.

Prove that the area of pentagon ABCDE is equal to the area of triangle GDF.

Sum

Solution


Since triangle EDG and EGA are on the same base EG and between the same parallel lines EG and DA.

Therefore,

A(ΔEDG) = A(ΔEGA)

Subtracting ΔEOG from both sides, we have

A(ΔEOD) = A(ΔGOA)              ...(i)

Similarly,

A(ΔDPC) = A(ΔBPF)              ...(ii)

Now

A(ΔGDF) = A(ΔGOA) + A(ΔBPF) + A(pen. ABPDO) 

= A(ΔEOD) + A(ΔDPC) + A(pen. ABPDO)

= A(pen. ABCDE)

Hence, proved.

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Chapter 16: Area Theorems [Proof and Use] - Exercise 16 (A) [Page 197]

APPEARS IN

Selina Concise Mathematics [English] Class 9 ICSE
Chapter 16 Area Theorems [Proof and Use]
Exercise 16 (A) | Q 8 | Page 197

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