Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

If ABCD is a kite how can I find angle C, when consecutive sides are congruent? (DA=AB, DC=CB)?

Attachment image

1 Answer

Relevance
  • Ash
    Lv 7
    1 month ago
    Favorite Answer

    Join DB

    ADB forms isosceles triangle with AD ≅ AB 

    m∠ADB = m∠ABD ... (1)

    In Δ ADB,

    m∠ADB + m∠ABD + m∠A = 180°

    from (1)

     m∠ADB + m∠ADB  +  120° = 180°

    2m∠ADB  = 60°

    m∠ADB = 30°

    m∠ADC =  m∠ADB +  m∠BDC

    85° = 30° + m∠BDC

    m∠BDC = 55°

    Since DC ≅ BC

    m∠DBC = 55°

    In Δ DBC,

    m∠BDC + m∠DBC + m∠C = 180°

    55° +  55° + m∠C = 180°

    m∠C = 70°

Still have questions? Get your answers by asking now.