Another way to solve this is to use the Midpoint Formula. The midpoint of a segment joining points

and

is

So the midpoint of your segment is

Perhaps it helps to see that the x-coordinate of the midpoint is just the average of the x-coordinates of the points. Ditto for the y-coordinate of the midpoint; just average the y's.
Answer:
a = 28 / √2
Step-by-step explanation:
Isosceles triangle therefor a = b
use pythagorean theorem
a² + a² = c²
2a² = 28²
a² = 28² / 2
Take the square root of both sides
a = 28 / √2
Oh shorter one inch from a foot rit?
One foot=12 in
12-1=11
11 inches