lol sure, i'd be glad, sometimes even I do look back to these elementary maths when my brain is fizzled with calculus

Haha

Let me tag you when I get stumped by those seemingly insurmountable questions 

cryotosensei

assuming the point between A and C to be say: P, we get a 

 10 + 10 + DP + (10-CP) = 10 + PD + CP + 12

PCD = 0.5 * CP * CD  = 0.5 * 4 * 10 = 20 cm²

science

Are you smarter than a 12-year-old?

assuming the point between A and C to be say: P, we get a $$\Delta$$PCD and a quad ABDP

so, as per problem, 
AB + BD + DP + DA = CD + PD + CP + 12
$$\implies$$ 10 + 10 + DP + (10-CP) = 10 + PD + CP + 12
$$\implies$$ 30 + PD - CP = 22 + PD + CP
$$\implies$$ 8 = 2 * CP
$$\implies$$ CP = 4

thus $$\Delta$$PCD = 0.5 * CP * CD  = 0.5 * 4 * 10 = 20 cm²

pretty simple :)