Draw \(AH,CK\perp BD;AM,BN\perp CD\)

\(\dfrac{S_{ABE}}{S_{ADE}}=\dfrac{AH.BE:2}{AH.DE:2}=\dfrac{BE}{DE}\Rightarrow\dfrac{BE}{DE}=\dfrac{50}{20}=\dfrac{5}{2}\)

\(\Rightarrow\dfrac{S_{BEC}}{S_{DEC}}=\dfrac{BE.CK:2}{DE.CK:2}=\dfrac{BE}{DE}=\dfrac{5}{2}\)

\(\dfrac{S_{ADC}}{S_{BDC}}=\dfrac{AM.DC:2}{BN.DC:2}=1\Rightarrow S_{ADE}+S_{DEC}=S_{BEC}+S_{DEC}\)

\(\Rightarrow S_{ADE}=S_{BEC}=20\left(units^2\right)\)

\(\Rightarrow S_{DEC}=20:\dfrac{5}{2}=8\left(units^2\right)\)

So, the answer is : \(20+50+20+8=98\left(units^2\right)\)