In δabc, m∠b = m∠c. the angle bisector of ∠b meets ac at point h and the angle bisector of ∠c meets ab at point k. prove that bh = ck.

First, let's illustrate the problem as shown in the picture attached. Then, let's make a two-column proof:

            Statement                                                       Reason
          m∠B = m∠C                                                       Given
             AB = AC                                        Isosceles Triangle Definition
       AK=KB=AH=HC                                      Angle Bisector Postulate
        ΔBKC = ΔHBC                                        Line BC is common side
             BH = CK   Corresponding parts of congruent triangles are congruent

Option 1 , Option 3 and Option 4 are correct.

Step-by-step explanation:

Number of customers using landlines decreases 10% per year.

Let x be the umber of customers using landlines in 2002.

⇒ Number of customer using landlines in 2003 =

                                                                               =

                                                                               = 0.9x

Number of customers using landlines in 2004 =  

                                                                              =

                                                                              =

                                                                              =

Therefore, from this Option 1 , Option 3 and Option 4 are correct.