Analyzing the Horizontal Side
Consider the points A(−8,5) and B(6,5). Since both points share the same y-coordinate of 5, the side AB is perfectly horizontal.
The length of side
AB is calculated by the difference in the
x-coordinates:
∣6−(−8)∣=14 units
This value represents the length of our rectangle. We will utilize this dimension for the final area calculation.
The Symmetry of the Circle
A rectangle inscribed in a circle shares the same center as the circle. By geometric symmetry, the center must lie on the perpendicular bisector of any side.
The midpoint
M of side
AB is calculated as:
M=(2−8+6,5)=(−1,5)
Since AB is horizontal, its perpendicular bisector is a vertical line passing through x=−1. Thus, the center of the rectangle must lie on the line x=−1.
The Intersection of Truth
The problem provides the equation of a diameter: 3y=x+7. Because the center of the circle must lie on all diameters, it must satisfy this equation.
We find the center by substituting
x=−1 into the diameter equation:
3y=−1+7
3y=6
y=2
The center of the circle and the rectangle is located at the point C(−1,2).
The Final Calculation
The vertical distance from the center
C (at
y=2) to the top side
AB (at
y=5) is:
5−2=3 units
Since the center is the midpoint of the rectangle, this distance represents half of the total height. Therefore, the total height of the rectangle is:
2×3=6 units
The area of the rectangle is the product of its length and height:
Area=14×6=84 square units
The final answer is 84.