We need to construct the perpendicular bisectors of at least two of the three sides.
The perpendicular bisector is the locus of points that ensures equal distance between any point on the line and the two ends of the segment.
The intersection of the two or three (congruent) perpendicular bisectors is the centre of the circumcircle.
Answer:
The angle between the ladder and the wall is of approximately 32 degrees 
, which agrees with the answer marked as "B" in the list of options.
Step-by-step explanation:
Notice that the wall and the floor make a right angle, and the ladder lining against the wall makes the hypotenuse of a right angle triangle.
See the attached image for explanation, and for the angle 
that we are trying to find, which is formed between the ladder and the wall.
Notice as well that the 8 ft section of the wall, is an "adjacent" side of the angle , and that the 5 ft segment between the wall and the base of the ladder is the "opposite" side to the angle.
We can then use the "tangent" of the angle which is defined as the quotient between the opposite side divided the adjacent side to investigate the measure of the angle . We will use the "arctangent" to solve for the angle:
which can be rounded to 
If the polygon ABCD rotates 90° counterclockwise then every point rotates the same. The coordinates of C´ are: B) (-7,-2)
Answer:
Then you don't change the sign.
Two like signs become a positive sign.
Two unlike signs become a negative sign.
