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sum of inner Angles in a Triangle allisonbrookephotography.com Topical rundown | Geometry overview | MathBits" Teacher sources Terms the Use call Person: Donna Roberts

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The amount of the actions of the interior angles of a triangle equals 180º.

You are watching: What is the measure of angle bcd? m∠bcd = degrees


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Solution: mA + mB + mC = 180 38 + x + (x + 2) = 180 40 + 2x = 180 2x = 140 x = 70 = m∠B x + 2 = 72 = m∠C


2. The angle in a triangle are represented by (4x - 6)º, (2x + 1)º and (x + 3)º. Is this a ideal triangle?

Solution: (4x - 6) + (2x + 1) + (x + 3) = 180 7x - 2 = 180 7x = 182 x = 26 (4x - 6)º = 98º (2x + 1)º = 53º (x + 3)º = 29º No. The triangle is obtuse.

3.
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Solution: mBCD = 56º. In ΔABC, 85º + 56º + mBCA = 180 mBCA = 39º mACD = 56º - 39º = 17º


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The angles in a triangle are in the ratio of 1 : 2 : 3. Discover the measure up of the angle in the triangle.

See more: What Does Fambam Mean Ing And Definition, Fambam Meaning And Definition


Solution: x + 2x + 3x = 180 6x = 180 x = 30 The angles room 30º, 60º, and 90º.

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In her previous studies of this theorem, girlfriend most likely saw how a triangle"s angles deserve to be cut off and rearranged to kind a directly angle the 180º (as displayed below).

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We now have to use much more sophisticated principles to develop that this organize is actually true. Throughout history, several different methods of evidence of this theorem have appeared. Let"s take a look at a couple of of these methods of proof.