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B+b = 45

B-b = 21

2B = 66

B = 33 cm

b = 45-21 = 12 cm

h = 2A /(B+b) = 1260/45 = 28 cm

Lo = BD = √21^2+28^2 = 7√3^2+4^2 = 35 cm

perimetro 2p = B+b+h+lo = 45+28+35 = 108 cm

In base al disegno:

{x+y=45                                                                         

{y-x=21

------------(sommo)

2y=66

Y=33 cm

{x+y=45                                                                         

{y-x=21

------------(sottraggo)

2x=24

X=12 cm

A=1/2*(12+33)*h----------> 630=45/2*h---------->h=AC=BE=630·2/45 = 28 cm

BD=teorema di Pitagora=sqrt(BE^2+ED^2)= √(28^2 + 21^2) = 35 cm

Perimetro= CD+BD+AB+AC=33 + 35 + 12 + 28 = 108 cm