Geometry in maths can means dealing with angles from a square or a rectangle.
Normally the question is to determine an unknown angle given some shape and angles.
However, mistakes can happen when basic knowledge of relationship between angles and shapes are not proper understood.
Here, I will stress on the square and rectangular matters. This is basic but can pose a tricky problem to the unwarys. Poor thing.....
Let's look at the diagram below.
This is so since the corner where angle A lies is 90 degree divided EQUALLY by half due to the diagonal lines reaching to the opposite side. (symmetrical sides).
However, if the side M and N are not equal in length, then angle A WILL NOT be 45 degree. It will depends on the ratio of side M and N.
Note this message and unnecessary mistake can be avoided.
Sometime it is to test the logical thinkng through maths, by not telling you angle A is 45 degree but stating that the box is a square.
This type of maths problem will require you to calculate another angle but using angle A which is not given.
It is tricky but good to have. Your brain will be stretched to make it "flexible" for future use.
Maths is good in this sense as it twists our mind and makes our life interesting!
Work hard as well as smart.
For more examples on avoiding unnecessary mistakes, visit this time calculation post.