Question

How many acute angles can a quadrilateral have?

Answer 1

`0`, `1`, `2` or `3`

Explanation:

The sum of the internal angles of a quadrilateral is `360^@`.

Hence the maximum number of acute angles a quadrilateral can have is `3`, since the `4`th angle will be forced to be greater than `90^@`.

In the following picture, the red square has no acute angles, the green kite has one acute angle, the blue rhombus has two and the gold kite has three.