10x5"+1 + 25x5"
(1) 3x5n+2 +10x51+1
Answers
Answer:
Given : ABCDE is a pentagon EG is drawn parallel to DA which meets BA produced at G and CF is drawn parallel to DB which meets AB produced at F
To prove: area(pentagon ABCDE) = area(∆DGF)
Proof:
Consider quadrilateral ADEG. Here,
area(∆AED) = area(∆ADG) ------------- (1)
[since two triangles are on same base AD and lie between parallel line i.e, AD||EG]
Similarly now, Consider quadrilateral BDCF. Here,
area(∆BCD) = area(∆BDF) ---------------- (2)
[since two triangles are on same base AD and lie between parallel line i.e, AD||EG]
Adding Eq (1) and (2) we get
area(∆AED) + area(∆BCD) = area(∆ADG) + area(∆BDF) ------------------ (3)
Now add area(∆ABD) on both sides of Eq (3), we get
area(∆AED) + area(∆BCD) + area(∆ABD) = area(∆ADG) + area(∆BDF) + area(∆ABD)
area(pentagon ABCDE) = area(∆DGF)
Hence proved.
Answer: