圆面积与π的近似值

GeoGebra 命令及参数

1. If(x > 0, f_5) → f
2. If(x > 0, g_5) → g
3. Circle(A, B) → c
4. Intersect(c, Circle[B, 2 * r_1 * sin(π / n)]) → C_1, C_2, ,
5. Polygon(B, C_1, n) → poly1, b, j_1, l_1, n_1, q_1, s_1, a_2, c_2, e_2, g_2, i_2, j, k_2, a, n_2, q_2, s_2, a_3, c_3, e_3, g_3, i_3, k, k_3, m_3, p_3, s_3, a_4, c_4, e_4, g_4, i_4, k_4, m, m_4, C, J, L, P, R, T, V, Z, B_1, s, E_1, G_1, I_1, K_1, M_1, O_1, Q_1, S_1, U_1, W_1, a_1, A_2, D_2, F_2, H_2, J_2, L_2, N_2, P_2, R_2, T_2, c_1, V_2, Z_2, B_3, D_3, F_3, H_3, J_3, L_3, N_3, e_1, h_1
6. Midpoint(B, C_2) → D
7. Line(A, D) → d
8. Intersect(Circle[A, r_1 / (sin(π / n) / tan(π / n))], d) → E, F
9. Intersect(Circle[A, F], Circle[F, 2 * r_1 * tan(π / n)]) → G, H, ,
10. Polygon(F, G, n) → poly2, i, k_1, m_1, p_1, r_3, t_1, b_2, d_2, f_2, h_2, j_2, f_1, l_2, m_2, p_2, r_2, t_2, b_3, d_3, f_3, h_3, j_3, e, l_3, n_3, q_3, t_3, b_4, d_4, f_4, h_4, j_4, l_4, q, n_4, I, K, O, Q, S, U, W, A_1, D_1, t, F_1, H_1, J_1, L_1, N_1, P_1, R_1, T_1, V_1, Z_1, b_1, B_2, E_2, G_2, I_2, K_2, M_2, O_2, Q_2, S_2, U_2, d_1, W_2, A_3, C_3, E_3, G_3, I_3, K_3, M_3, O_3, g_1, i_1
11. Rotate(poly2, 90*°, A) → poly2'