GeminiHeat wrote:
A triangle in the xy-coordinate plane has vertices with coordinates (7, 0), (0, 8), and (20, 10). What is the area of this triangle?
A. 72
B. 80
C. 87
D. 96
E. 100
Area of triangle = \(\frac{1}{2}|20(8 - 0) + 0(0 - 10) + 7(10 - 8)| = \frac{174}{2} = 87\)
Alternate Approach:
Draw lines CD and CE (as shown in the figure)
Area of triangle ABC = Area of rectangle ODCE - Area of triangle AOB - Area of triangle BDC - Area of triangle CEA
= \((20)(10) - \frac{1}{2}(7)(8) - \frac{1}{2}(13)(10) - \frac{1}{2}(20)(2)\)
= \(200 - 28 - 65 - 20\)
= \(87\)
Attachments

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