ABCD is a parallelogram, G is the point on AB such that AG = 2GB, E is a point of DC , such that CE = 2DE and F is the point of BC such that BF = 2FC. prove that :
1) ar (quad ADEG) = ar(quad GBCE)
2.) ar( triangle EBG) = 1/6 ar( quad ABCD)
3) ar( triangle EFC) = 1/2 AR(triangle EBF)
4 ) ar( triangle EBG )= ar( triangle EFC)
5 ) find what portion of the area of parallelogram is the area of triangle EFG.
"meritnation expert gursheen kaur has answered my question, but the method was incorrect.she supposed that G is the mid-point of AB and F is the midpoint of BC. but it's wrong method. please experts firstly read the question properly before answering it."
given: ABCD is a parallelogram. AG=2GB,CE=2DE and BF=2FC.
(i)
TPT: area(quad ADEG)=area(quad GBCE)
construction: from point E and G draw the lines intersecting AB at N and DC at M respectively.
proof: since ABCD is a parallelogram. AB=CD
BG = 1/3 AB and DE=1/3 DC=1/3 AB
therefore DE=BG
here ADEN is a parallelogram [since AN is parallel to DE and AD is parallel to NE]
quadrilateral BCMG is also the parallelogram.
area (parallelogram ADEN)=area(parallelogram BCMG )............(1) [since DE=BG and AD=BC parallelogram with corresponding sides equal]
area(Δ NEG)= area(ΔEGM)..........(2) [diagonals of a parallelogram divide it into two equal areas]
adding (1) and (2)
area (parallelogram ADEN)+area(ΔNEG)=area(parallelogram BCMG )+area(ΔEGM)
⇒area(quad ADEG)=area(quad GBCE)
therefore (i) part is proved
(ii)
TPT: area(ΔEBG)=1/6 area(ABCD)
proof:
let the distance between the parallel lines AB and CD be h.
therefore area (ABCD)= AB*h............(1)
since AG=2BG, and AG+BG=AB
therefore BG=1/3 AB
area of (ΔEBG)=............(2)
from (1) and (2), we have area(ΔEBG)=1/6 area(ABCD)
therefore (ii) part is proved.
(iii)
TPT: area(ΔEFC)=1/2area(ΔEBF)
proof:
let the distance between the parallel sides EN and CB be x.
therefore area(ΔBEF)=.............(1)
area (ΔECF)=......(2)
which is (iii) result.
now try to solve the (iv) and (v) part by yourself , if you face any difficulty then do get back to us.