Krishna
0

Step 1: Find the angle   \angle ABC

             NOTE: From the figure two angle forming the straight line

                           \angle ABC   = 180 - 116

                                         = 64


Step 2: Find all the unknown interior angles of the isosceles triangles ABC

           Skill 1: Know about the interior angle of isosceles triangles.

                      NOTE: Sum of the interior angles of the

                        isosceles triangle = 2 * (equal angle) + angle = 180 \degree


           Skill 2: Set up an equation equating 180°

                      EXAMPLE: \triangle ABC is an isosceles triangle and

                                 therefore \angle CAB = \angle ABC = 64

           Skill 3: Substitute the known angle and simplify for the unknown angles

                          2(64) + \angle ACB = 180

                             \angle ACB = 180 - 128

                             \angle ACB = 52


Step 3: Find the angle \angle DCE

            NOTE: Vertical angles are equal

                  So, \angle DCE + \angle ACB = 52


Step 4: Find the angles in another isosceles triangle CDE

             NOTE: \triangle CDE is an isosceles triangle

                           So \angle DCE = \angle CDE = 52


Step 5: Find the angle \angle CED

             \angle CED =180 - ( \angle DCE + \angle CDE )

                 \angle CED = 180 - 52 - 52 = 76 \degree