Calculating the energy of trapezoid wave Here is the trapezoid wave,although i know we can use $\int^{4}_0 |x(t)|^2dt$ to calculate its power,but i want to divide this trapezoid to right triangle$(t=0$~$2)$,and a square ($(t=2$~$4)$).

I know the the triangle effective voltage is $V_{eff}=\frac{V}{\sqrt{3}}$,and i want to use $P=\frac{V_{eff}^2}{R}$ to calculate the power ,  but i am not sure about which  triangle is correct,i mean,for which triangle(a or b or c),i can use $\frac{V}{\sqrt{3}}$ to calculate its power,or are these three wave's power the same,but different in energy?
it seems that there power are the same,but there energy are not the same ,because energy=power $\times$ time,and time are different,so their energy are not the same too