Question

1.Trapezul isoscel ABCD, cu AB || CD, AB>CD, are AD=CD=BC=36, si m(∡B)=60 .Calculati
a) masura unghiului acd
b)perimetrul trapezului

Answer 1

CE SI DF _l_ AB

<) B  =60 grade => <) BCD =180-60 =120 gr.; <)C=D =120 gr

triungh.ADC =isoscel <)DAC =ACD = (180-120) :2 = 30 grade

in triungh. BCE <) B =60 gr. => <) BCE =30 gr. =>BE =BC/2 =36/2 =18 cm

BE =AF =18 cm ;  EF =CD =36 cm

=>AB =18+36+18 =72 cm

P abcd =3*36+72 =108+72 =180 cm