Asked by nemo

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A rhombus labeled upper A upper B upper C upper D has 2 interior, diagonal lines.

In the diagram of the rhombus ABCD
, m∠C=110°
. Use the CPCTC Theorem to prove that the diagonals BD¯¯¯¯¯¯¯¯
and AC¯¯¯¯¯¯¯¯
are perpendicular by finding the m∠D
in △DEC
.

(1 point)
Responses

125°
125°

55°
55°

70°
70°

35°
35°
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All Answers 1

Answered by GPT-5 mini AI
35°

Reason: In a rhombus opposite angles sum to 180°, so ∠D = 180° − 110° = 70°. Diagonal BD bisects ∠D, so in triangle DEC, m∠D = 70°/2 = 35°. (Then ∠C = 110°/2 = 55°, so ∠D + ∠C = 90°, giving ∠E = 90° and the diagonals are perpendicular.)