3-1 內角與外角

$$30\degree$$

$$60\degree$$

$$90\degree$$

$$120\degree$$

$$30\degree$$

$$60\degree$$

$$90\degree$$

$$120\degree$$

60

90

180

360

60

90

180

360

$$50\degree$$

$$70\degree$$

$$90\degree$$

$$110\degree$$

$$\angle1+\angle2=\angle3$$

$$\angle2+\angle3=\angle1$$

$$\angle1+\angle3=\angle2$$

$$\angle1=\angle2=\angle3$$

$$\angle1+\angle2=\angle3+\angle4$$

$$\angle1+\angle3=\angle2+\angle4$$

$$\angle1+\angle2+\angle3=\angle4$$

$$\angle2+\angle3+\angle4=\angle1$$

$$\angle1+\angle2=\angle3+\angle4$$

$$\angle1+\angle3=\angle2+\angle4$$

$$\angle1+\angle2+\angle3=\angle4$$

$$\angle2+\angle3+\angle4=\angle1$$

$$180\times n$$

$$360\times n$$

$$180\times\left(n-2\right)$$

$$360\times\left(n-2\right)$$

$$180\times n$$

$$360\times n$$

$$180$$

$$360$$