Question

Can all the four angles of a quadrilateral be obtuse angles? Give a reason for your answer.

Answer 1

An obtuse angle is greater than ${90}^0$

According to the quadrilateral angle sum property, the sum of all four angles of a quadrilateral is ${360}^0$.

If we take all four angles greater than ${90}^0$

Then, their sum will be obviously greater than ${360}^0$.

Hence, all four angles of a quadrilateral cannot be obtuse angles.