Serge Lang, Geometry(2nd ed.), Exercise 1.A.6, Solution

Serge Lang, Geometry(2nd ed.), Exercise 1.6.21, Solution

Serge Lang, Geometry(2nd ed.), Exercise 1.6.16, Solution

Exercise 1.6.16 (Theorem 1-7)

「平行四邊形對角互補(相加為平角，$180^{\circ}$)。」

見Exercise 1.6.15之解答。

(解答結束)

Serge Lang, Geometry(2nd ed.), Exercise 1.6.15, Solution

Serge Lang, Geometry(2nd ed.), Exercise 1.6.4, Solution

Serge Lang, Geometry(2nd ed.), Exercise 1.6.3, Solution