we can divide the composite shape into on quadrilateral and triangle as shown in the diagram. since the line that joins the two shape is parallel to the base AB, the angle DEC is 85°.The angle CEA is 180°- angle DEC = 180-85=95. Angle BCE is sum of angle CEA, ABC and EAB subtracted from360°= 360°-(95+95+85)=85°. Angle DCE is 120°- ECB=35°. So, angle CDE = 180°-(35°+85°)= 60°. For reference see the diagram.
Using the mid-point concept, it is found that point B is located at coordinates (-6.5, 0).
<h3>What is the midpoint concept?</h3>
The midpoint between two points is the halfway point between them, and is found using the mean of the coordinates.
The center is the midpoint of the two coordinates of the diameter, hence:

For the x-coordinate:

x + 0.5 = -6
x = -6.5
For the y-coordinate:

y + 6 = 6
y = 0
More can be learned about the mid-point concept at brainly.com/question/10956693
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The standard deviation is 1, I believe...