Which is the best estimate of -14 1/9 (-2 9/10)

The answer is:  [D]:  "42" .

Explanation:  

Consider the "1/9" to be close to "1/10" ; (that is; "0.1" ; since "0.1 = 1/10" ) .

Note that a "negative value" multiplied by a "negative value" equals a "positive value". 

Round the "14.1" to "14" ; and the "2.9" to "3" ;


-14.1 * -2.9 ≈  14* 3 = 42 . 

Area of circle = pi * radius^2radius is given to be 1/2 inchespi * (1/2)^2 = pi/4 inches^2 = 0.785 inches^2