Answer:
A= 15
Explanation:
First step is we make an equation. As we know, the line is known as a straight angle, which always equals 180°. To make the equation, we are going to plug in the information we had, 4a° and 120°, plus our new information which is 180°. The equation should look like this.
4a°+120°=180°
We then subtract 120 from each side which will simply it to
4a°=60
We then have the leave the variable, a, by itself. To do that we must divide 4 to each side which will leave us with our answer.
a°=15
To verify our answer we can plug 15 back to the equation.
4(15)°+120°=180° = 60°+120°=180° = 180°=180°