Question 432763
Let's the smaller diagonal x cm, then the greater will be x+4 cm. As you know the rhombus diagonals are perpendicular and bisect each other.With these knowledges applying Pythagorean theorem we have:

 {{{10^2-(x+4)^2/4=x^2/4}}}, solving this equation we find the diagonals.

 {{{x^2+4x-392=0}}}, one diagonal is D1=18cm and the other D2=18+4=22cm

As you know the area of rhombus is: {{{A=(1/2)*D1*D2=(1/2)*18*22=198cm^2}}}