I am supposed to use the following 8 theorems only to prove the above prepositions:
Theorem 1: If a ray stands on a line , then the sum of the adjacent angles formed is $180 $deg.
Theorem 2: If two lines intersect , then the vertically opposite angles are equal.
Theorem 3: If a transversal cuts two parallel lines, then each pair of alternate angles are equal, and the interior angles on the same side of the transversal are supplementary.
Theorem 4: Lines which are parallel to the same line are parallel to each other.
Theorem 5: The sum of the three angles of a triangle is $180$deg.
Theorem 6: If one side of a triangle is produced , the exterior angle so formed is equal to the sum of the interior opposite angles.
Theorem 7: The angles opposite to equal sides of a triangle are equal in an isosceles triangle.
Theorem 8: The bisector of the vertical angle of an isosceles triangle bisects the base and is perpendicular to the base.
I tried to get the solution but could not apply theorems 7 and 8 since it is a right angle triangle. I don't use concept of rotation. I use ASA, SAS, SSS and RHS Postulates and converse of theorem 1,3,7 and 8. can anyone tell me how the proof looks like? Thanks in advance...Srikanth