You can just use the tn formula to solve this tn= t1 + (n-1)d
Pythagorean Therom
a^2 + b^2 = c^2
5^2 +b^2 = 7^2
25=b^2 = 49
49-25=b^2
49-25=14
b^2=24
b=sqrt24
sqrt24=4.89898
Answer=B
The explanatory variable is another term for the independent variable. The independent variable is the 'thing' that YOU decide to change/manipulate in an experiment. The type of nail polish given was the independent variable for this experiment.
t must equal √2h/g but I don't see that in the choices above