In primul rand calculam lungimea si latimea dreptunghiului (initial):
L = 50dm
l = [tex] \frac{3}{5} * L = \frac{3*50}{5} = 30dm [/tex]
a) P = 2L + 2l = 2*50 + 2 * 30 = 160dm
b) A = l * L = 50 * 30 = 1500[tex]dm^2[/tex] = 15[tex]m^2[/tex]
c) L = 50dm - 0.5 cm = 500cm - 0.5cm = 499.5 cm = 4995mm
l = 30dm + 1cm = 300cm + 1cm = 301cm = 3010mm
A = l * L = 15034950[tex]mm^2[/tex]