Question

In the diagram, two lines intersects. Which statement is not true ?

Answer 1

Given:

The diagram shows two intersecting lines making angles 1,2,3,4

Now,

We know, angles on a straight line sum to 180 degrees.

So, using this property, we have

$\begin{gathered} m\angle1+m\angle2=180 \\ m\angle1+m\angle3=180 \\ m\angle3+m\angle4=180 \end{gathered}$

But angles 1 and 4 are vertically opposite angles so they are equal.

Hence,

$m\angle1=m\angle4$

Hence,

$m\angle1+m\angle4\ne180$

Therefore, option 1 is not true.

Option 1 is correct answer.