Answer:
[tex]\huge\boxed{\boxed{\mathbb{B)70°}}}[/tex]
Step-by-step explanation:
to understand this
you need to know about:
- vertical angle
- equation
- PEMDAS
given:
- [tex]\sf m\angle ABC=3x-20[/tex]
- [tex]\sf m\angle DBF=x+40[/tex]
tips and formulas:
- Vertical Angles are the angles opposite each other when two lines cross
- vertical Angles are equal
let's solve:
according to the question
3x-20=x+40
=>3x-x=40+20
=>2x=60
=>x=60/2
x=30
given [tex]\sf m\angle ABC=3x-20[/tex]
substitute the value of x
30×30-20
simplify
90-20
70
