Have a look at 1/8 and 19/24. Convert 1/8 to 3/24. Note that 19/24 is obtained by adding 16/24 to 3/24. Thus, the common difference is 16/24, or 8/12, or 4/6, or 2/3.
Area of decagon is given by: Area=1/2(nsr) where: n=number of sides s=side length r=height thus the area will be given by: Area=1/2(10*4*6.2) Area=124 cm^2
