x -wskażnik krotności
a = 2x
b = 3x
H = 4x
P_c=2*P_p+P_b
P_p=a*b=2x*3x=6x^2
P_b=2*a*h+2*b*H=2*2x*4x+2*3x*4x=16x^2+24x^2=40x^2
P_c=2*6x^2+40x^2=12x^2+40x^2=52x^2
P_c=13[cm^2]
52x^2=13|/52
x^2=\frac{13}{52}=\frac{1}{4}
x=\frac{1}{2}
H=4*\frac{1}{2}=2
Odpowiedź B