Question

text to speech calculator highlighter >> what is ( mangle cbd )? ( mangle cbd=)

Explanation:

Step1: Find the measure of ∠ABD

Use the exterior - angle theorem. In △ABD, ∠ADB = 80°, ∠A = 60°.
Since ∠ADB=∠A + ∠ABD (exterior - angle theorem: the measure of an exterior angle of a triangle is equal to the sum of the measures of the two non - adjacent interior angles), then ∠ABD=∠ADB - ∠A.
∠ABD = 80°−60° = 20°.

Step2: Find the measure of ∠CBD

In △BCD, use the angle - sum property of a triangle. Let ∠CBD=x.
We know that ∠BDC = 180°−80°=100° (linear pair: ∠BDC + ∠ADB=180°) and ∠C = 25°.
By the angle - sum property of a triangle (∠CBD+∠C + ∠BDC = 180°), we have x+25°+100° = 180°.
x=180°−(25° + 100°).
x = 55°.

Answer:

55