You are watching: The measure of an exterior angle of a triangle is equal to the sum of the measures of the two

** Exterior angles in a Triangle ** snucongo.org Topical summary | Geometry synopsis | MathBits" Teacher sources **Terms that Use contact Person:** Donna Roberts

An exterior edge of a triangle is an angle created by one next of the triangle and also the expansion of an adjacent side the the triangle.

**FACTS:**• Every triangle has 6 exterior angles, two at every vertex.• angles 1 through 6 space exterior angles.• an alert that the "outside" angle that room "vertical" to the angles inside the triangle space NOT referred to as exterior angle of a triangle.

The measure of an exterior edge of a triangle is same to the sum of the steps of the two non-adjacent internal angles. (Non-adjacent interior angles may also be described as remote interior angles.)

**FACTS:**• one exterior ∠ is same to the addition of the two Δ angles not right next to it. 140º = 60º + 80º; 120º = 80º + 40º; 100º = 60º + 40º • an exterior angle is supplementary come its surrounding Δ angle. 140º is supp to 40º • The 2 exterior angles at each vertex space = in measure because they room vertical angles. • The exterior angle (taken one at a vertex) always total 360º

*Solution: utilizing the Exterior angle Theorem*

**145 = 80 + x**

*x*= 65 Now, if you forget the Exterior angle Theorem, you can still gain the price by noticing that a directly angle has actually been created at the vertex of the 145º angle.**See example 2.***Solution:*i forgot the Exterior edge Theorem.**The angle adjacent to 145º will form a directly angle along with 145º adding to 180º. The angle is 35º. Now use preeminence that amount of ∠s in Δ = 180º. 35 + 80 +**

See more: How To Get Darth Vader In Soul Calibur 4 ? How Do You Get Darth Vader In Soul Calibur

Find m∠DBC.*x*= 180 115 +*x*= 180*x*= 65See more: How To Get Darth Vader In Soul Calibur 4 ? How Do You Get Darth Vader In Soul Calibur

Find m∠DBC.

**Solution:**

*∠BDC*is one exterior angle for Δ*ABD*.*m∠BDC*= 35 + 25*m∠BDC*= 60º 180*= m∠DBC*+ 60 + 60*m∠DBC*= 60º