80 is the product of Diego's height and 5.
Use the variable d to represent Diego's height.

The expression is 5d = 80. 80 ÷ 5 = 16. Therefore, the variable D is 16.

mental cunning

explanation:

he is often referred to as a man of twists and turns

the mistake in the pattern is that :

b. the decimal point was moved one too many place values each time

the correct pattern could be made by :

b. moving the decimal point to the right the same numbers of place values as the exponents