Beatrice threw a stone one and seven fourteenths yards. Tilly threw a stone nine fourteenths of a yard. What is a reasonable estimate of the difference between their two throws? 1 yard
one and one half yards
2 yards
two and one half yards

1 yard

Step-by-step explanation:

7/14 is 1/2 while 9/14 is greater than 1/2 but a lot less than a whole. So a strong estimate would assume that it is (1 1/2)-(1/2) for the approximate difference in  their throws were  

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.