(B+C)= 2*(4/sq root 5)* (4/sq root 5)= 32/5 = 6.4
D 不用三角如何計算?
圓麵積 = 3.14 * 16 = 50.24
A = 16 - D - 6.4 =
X = 16 - A - 1/4 * 50.24 = 16 - A - 12.56 =