Question

Use the relationship between the angles in the figure to answer the question.

Which equation can be used to find the value of x?

Drag and drop the equation into the box.

Answer 1

A straight line is 180° no matter how many times it is divided

So ..

31° + x° + 40° = 180°
71° + x ° = 180°
x° = 180° - 71°
x° = 109°

Answer 2

We know that the angles add to a 180° angle.
We get the equation then:

`31+x+40=180`
And the above equation is equivalent to this one:

`x=180-(31+40)`