Triangle abc and triangle BDC have vertices a(-6,-7),b(-6,4),c(2,-7)and d(8,4) what is the area in square units of trapezoid abdg which is formed by the two triangles

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Answer 1

Add point E(8,-7) to the figure to create rectangle ABDE. The area of the rectangle is AB*BD. Length of AB=4-(-7)=11 and length of BD=8-(-6)=14, so area of ABDE is 11*14=154. In right-angled triangle CDE, CE=8-2=6 and ED=AB=11. Area of triangle CDE is (1/2)(CE*ED)=(1/2)*6*11=33. So the area of ABDC=area of ABDE-area of CDE=154-33=121.