Mate clasa a VII a=Geometrie
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Răspuns:
Explicație pas cu pas:
ABCD- romb
BD= bisectoare
∡BDC=x
∡BDC= ∡A/3
³⁾x= ∡A/3
3x=∡A
∡D= 2x
∡B=2x
∡C= 3x
∡A=3x
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3x+3x+2x+2x=360°
10x=360
x= 360:10
x= 36°
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∡D= 2*36=72°
∡B=72°
∡A= 3*36=108°
∡C= 108°
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b)
∡C=2x+6
∡A= 2x+6
∡D=x
∡B=x
2x+6+2x+6+x+x=360°
2x+2x+x+x= 360-6-6
6x= 348
x= 348:6
x= 58 °
∡A= 2x+6
∡A= 2*58+6
∡A=122°
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∡A=122°
∡D=58°