237 Derivation of Golden Ratio by a right trangle

236 Derivation of Golden Ratio By trapezoid

235 Two tangents at the extremities of the diameter of a circle

234 Find the size of the dihedral angle B−AP−C

233 Given the triangular pyramid P−ABC such that AB=BC=2

232 A trangle geometric shape

231 A trangle with dynamic points on two sides and forming an isosceles triagnle for answer

230 A trangle with dynamic points on two sides and forming an isosceles triagnle

229 Goden ratio triangle for determination value of sin 18degree

228 Goden ratio triangle for determination value of cos 36degree

227 Goden ratio triangle with 36 degree and 72 degree internal angles

226 Given quadrilateral ABCD Prove the distance from O to EB B is equal to that from O to ED