Question

In a geometry class, the students were asked to prove the theorem below by contradiction.

Theorem: In a quadrilateral, there cannot be more than three obtuse angles.

Heather begins the proof with an assumption. Which statement will she most likely use as an assumption?

Let one angle of a quadrilateral be acute and the other three angles obtuse.

Let all angles of a quadrilateral be obtuse.

Let only one angle of a quadrilateral be obtuse.

Let one angle of a quadrilateral be obtuse and the other three angles acute.

Answer 1

i think Let all angles of a quadrilateral be obtuse.
That would be contradictory to the theorem.

Answer 2

That's what I thought as well. I wasn't sure. And I was right. Thank you.

Answer 3

My Pleasure.