B because in commutative property of addition the numbers switch but they do not change the sign nor the numbers. hope this helped
∠13 = 70.5° [Vertically Opposite angles]
∠13+∠14=180° [Linear pair]
70.5°+∠14=180°
∠14=180-70.5
∠14=109.5
∠15=∠14=109.5 [Vertically opposite angles]
∠13=∠12= 70.5° [Co-interior angles]
∠12=∠10= 70.5° [Vertically Opposite angles]
∠14=∠11=109.5 [Co-interior angles]
∠9=∠11= 109.5 [Vertically opposite angles]
∠13=∠7= 70.5° [Alternate interior angles]
∠7=∠5=70.5° [Vertically Opposite angles]
∠7+∠8=180° [Linear Pair]
70.5+∠8=180
∠8=180-70.5
∠8=109.5°
∠8=∠6= 109.5° [Vertically Opposite angles]
∠6=∠3=109.5° [Co-interior angles]
∠7=∠2=70.5° [Co-exterior angles]
∠2=∠4= 70.5° [Vertically Opposite angles]
∠3=∠1= 109.5° [Vertically Opposite angles]

<h3>Measures of all angles in sequence⤵️</h3>
- ∠1= 109.5°
- ∠2= 70.5°
- ∠3= 109.5°
- ∠4= 70.5°
- ∠5= 70.5°
- ∠6= 109.5°
- ∠7= 70.5°
- ∠8= 109.5°
- ∠9= 109.5°
- ∠10= 109.5°
- ∠11= 70.5°
- ∠12= 109.5°
- ∠13= 70.5°
- ∠14= 109.5°
- ∠15= 109.5°
- ∠16= 70.5°
Answer:
Basic Definitions of Geometry
A collinear set of points is a set of points all of which lie on the same straight line.
A noncollinear set of points s a set of three or more points that do not all line on the same straight
line.
A Line has no end points.
A Ray has one end point.
. Line Segment has two end points
Congruent segments are segments that have the same measure.
The Midpoint of a line segment is a point of that line segment that divides the segment into two
congruent segments.
The Bisector of a line segment is any line, or subset of a line that intersects the segment at the midpoint.
An Angle is a set of points that is the union of two rays having the same endpoint.