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Question Number 12930 by tawa last updated on 07/May/17

Answered by ajfour last updated on 07/May/17

Commented by ajfour last updated on 07/May/17

by parallel axes theorem:  ((DF)/(a+c)) = (b/(a+b+c))     .....(i)  ((EG)/(a+b )) = (c/(a+b+c))   .......(ii)  here we also have  (a+b)^2 +(a+c)^2 =(a+b+c)^2   (a+b)^2 +a^2 +2ac+c^2 =                   (a+b)^2 + c^2 +2(a+b)c  ⇒ a^2 = 2bc      ....(iii)  from (i) & (ii):  DF+EG =((ab+bc)/(a+b+c))+((ac+bc)/(a+b+c))                     = ((ab+2bc+ac)/(a+b+c))                    = ((ab+a^2 +ac)/(a+b+c))                   = ((a(a+b+c))/(a+b+c))  = a =DE       = 2017 .

$${by}\:{parallel}\:{axes}\:{theorem}: \\ $$$$\frac{{DF}}{{a}+{c}}\:=\:\frac{{b}}{{a}+{b}+{c}}\:\:\:\:\:.....\left({i}\right) \\ $$$$\frac{{EG}}{{a}+{b}\:}\:=\:\frac{{c}}{{a}+{b}+{c}}\:\:\:.......\left({ii}\right) \\ $$$${here}\:{we}\:{also}\:{have} \\ $$$$\left({a}+{b}\right)^{\mathrm{2}} +\left({a}+{c}\right)^{\mathrm{2}} =\left({a}+{b}+{c}\right)^{\mathrm{2}} \\ $$$$\left({a}+{b}\right)^{\mathrm{2}} +{a}^{\mathrm{2}} +\mathrm{2}{ac}+{c}^{\mathrm{2}} = \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\left({a}+{b}\right)^{\mathrm{2}} +\:{c}^{\mathrm{2}} +\mathrm{2}\left({a}+{b}\right){c} \\ $$$$\Rightarrow\:{a}^{\mathrm{2}} =\:\mathrm{2}{bc}\:\:\:\:\:\:....\left({iii}\right) \\ $$$${from}\:\left({i}\right)\:\&\:\left({ii}\right): \\ $$$${DF}+{EG}\:=\frac{{ab}+{bc}}{{a}+{b}+{c}}+\frac{{ac}+{bc}}{{a}+{b}+{c}} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:=\:\frac{{ab}+\mathrm{2}{bc}+{ac}}{{a}+{b}+{c}} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:=\:\frac{{ab}+{a}^{\mathrm{2}} +{ac}}{{a}+{b}+{c}} \\ $$$$\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:=\:\frac{{a}\left({a}+{b}+{c}\right)}{{a}+{b}+{c}}\:\:=\:{a}\:={DE} \\ $$$$\:\:\:\:\:=\:\mathrm{2017}\:. \\ $$$$ \\ $$$$ \\ $$

Commented by tawa last updated on 07/May/17

God bless you sir

$$\mathrm{God}\:\mathrm{bless}\:\mathrm{you}\:\mathrm{sir} \\ $$

Commented by tawa last updated on 07/May/17

Please sir what is the name of the application you used to draw the diagram

$$\mathrm{Please}\:\mathrm{sir}\:\mathrm{what}\:\mathrm{is}\:\mathrm{the}\:\mathrm{name}\:\mathrm{of}\:\mathrm{the}\:\mathrm{application}\:\mathrm{you}\:\mathrm{used}\:\mathrm{to}\:\mathrm{draw}\:\mathrm{the}\:\mathrm{diagram} \\ $$

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