Question

It is possible for 2 lines to

intersect in such a way
that 3 of the angles
formed have measures 20,
70, and 20.?

Sometimes true,
Never true,
Always true.

Answer 1

sometimes true

Explanation:

Given, two straight lines intersect each other in such a way that one of the angles formed measure 90°.

We know that, lines which intersect to form a right angle are known as perpendicular lines

In the above figure , AB is perpendicular to CD

Considering ∠AOC=90°

Now,

∠AOC+∠AOD=180° [Linear pair]

90°+∠AOD=180°

∠AOD=90°

Similarly,

∠AOC+∠BOC=180° and ∠BOD+∠AOD=180° [Both making linear pair]

So, we get ∠BOC=90° and ∠BOD=90°

Hence, ∠AOC=∠AOD=∠BOC=∠BOD=90°