H
E
E
L
E
M
E
N
T
S
the four straight lines GE, GF, GH, GK are equal to one another.
Therefore
the circle the circle described with center G and distance one of the straight lines GE, GF, GH, GK will pass also through the remaining points.
And
It will touch the straight lines AB, BC, CD, DA, because the angles at E, F, H, K are right.
