Question

(Thank you for any help that you can offer, but please; if you ARE NOT COMPLETELY SURE of your answer, refrain from answering. I would hate to have someone stealing the points from someone who might have the correct answer.)

All quadrilaterals have interior angles that sum to 360°.
True or False?

Answer 1

It is true, how??Here is explanation:

Consider a quadrilateral ABCD .Join diagnol AC so two triangles ABC & ACD will form.
Sum of interior angles of ABC is 180 and that of ACD is 180 as well.So, the total sum of the interior angles of ABC & ACD is 360 which is the sum of interior angles of quadrilateral itself.