Vetical angles are the angles that are opposite each other when two lines intersect. (Technically, these two lines need to be on the same plane)
In the picture on the left,
1 and
2 are vertical angles. Likewise,
A and
B are vertical. Vertical angles are always
congruent (equal).
m
X in the diagram on the left is 157° since its vertical angle is 157°.
Use the theorem that vertical angles are congruent to find the value of x in the problems below.
What is the m
B on the left?
Angle B
Angle B is 130°
Vertical Angle problems can also involve algebraic expressions. To find the value of x, set the two vertical angles equal then solve the equation:
x+5=2x-3
x=8
What is the value of x?
Answer
x-2 =133 x = 135°
What is the value of x?
Answer
2x+5 = 105°
2x = 100
½(2x = 100) x = 50
Use the vertical angles theorem to solve for x
Answer
4x +7 = 131°
4x = 124
¼(4x = 124) x = 31
Find the value of x in the picture on the left
Answer
Use your knowledge of vertical angles to solve for x
Answer
Solve for x
Answer
Use vertical angles to find the value of x
Answer
Use vertical angles to find the value of x
Answer
Use vertical angles to solve for x
Answer
