Exercise 3: Prove that the points B, O and A are aligned.

Complete the following proof :

As the triangle OBC is at , the angle BCO measures .

In the triangle OBC, the sum of the angles equals 180°.

Thus angle BOC = 180 - 2 x =

As the triangle COD is at , the angles COD and CDO are .

In the triangle OCD , the sum of the angles equals 180°.

Thus angle COD = (180 - ) : =

As the triangle OAD is at , its acute angles are .

Thus angle DOA = - =

Thus angle BOA = 94 + 34 + = .

Thus the points B, O and A are aligned.