Since Neil Armstrong was the first person to walk on the. moon, the contrapositive is

If nobody walked on the moon, then Neil Armstrong didn't

Step-by-step explanation:

The contrapositive flips the sign of "Neil Armstrong"  and the "moon," and also switches their position, so you will switch the hypothesis and conclusion as well

option a is correct.

step-by-step explanation:

scale factor: it is used to find proportional measurements.

proportions means having the same ratio.

scale factor is the ratio of the model measurement to the actual measurement in a simplest form.

or we can say that the ratio of any two corresponding lengths in two similar geometric figures

if the scale factor is more than 1, then it is an enlargement,

if the scale factor less than 1, then it is a reduction.

given the two geometric figure:

by definition of proportions, we have