It is true of Egyptian history that the Old Kingdom was the time of the construction of the great pyramids. This period was the time that the Egyptian civilization was at its peak.
Explanation:
you would either take and add them together to equal 90 or take them separate like for example 4x+1=90
it would be equal to 90 because they are complementary angles which add up to 90
-hope this helps
C. It contains no architectural elements
