A = bh/2
2a = bh
2a/b = h
h = 2a/b
The correct answer is:
C. They are similar because the corresponding sides of kites KELY and BRAD all have the relationship 2:1.
Using the distance formula,

the lengths of the sides of BRAD are:

The lengths of the sides of KELY are:

Each side of KELY is twice the length of the corresponding side on BRAD. This makes the ratio of the sides 2:1 and the figures are similar.
First, subtract the two values:
16 - 15.4 = 0.6
Now divide this to the actual area:
0.6 / 15.4 = 0.038961039
Multiply by 100:
0.038961039 * 100 = 3.8961039
So the percent error is approximately 3.9%