soft clay and wet and sandy soil as they are more likely to collapse or corrode over time especially the wet and sandy soil which will erode with rain or water
Answer:
.
Explanation:
We are given that,
In △EFG,


To find: 
As we know that, angles opposite to the congruent sides of a triangle are congruent.
Thus, In △EFG
if
and 
then it implies 
Hence, we get
.
An acute angle is less than 90 degree ;)