Răspunsuri

2014-05-29T14:25:47+03:00
A)P=3l=3*3 \sqrt{5} =9 \sqrt{5}
b)P_{romb} =4l=60cm rezulta l= \frac{60}{4} =15cm
Notam cu O intersectia diagonalelor. Intr-un romb diagonalele sunt perpendiculare si intersectia lor formeaza segmente congruente. Deci DO=OB=12CM
In triunghiul AOB se aplica TP:  AB^{2} = AO^{2} + OB^{2}  \\ AO^{2}=AB^{2} -OB^{2}=15^{2} - 12^{2} =225-144=81 \\ AO=9cm \\ AC=AO+OC=2AO=18cm
 A_{romb} = \frac{ d_{1}* d_{2} }{2} = \frac{AC*DB}{2} = \frac{18*24}{2} = \frac{432}{2} =216cm ^{2}
Deasemenea, intr-un romb avem:
 A_{romb}=h*l \\ 216=h*15 \\ h= \frac{216}{15} 14,4cm
La final am mancat un egal : =14,4cm !
Adyilye ce inseamna acel ,, l ,, ?
l adica latura ?
ms