Question

A(6,1),B(8,2) and C(9,4) are the vertices of a parallelogram ABCD. If E is the midpoint of DC, find the area of `Delta` ADE.

Answer 1

P is MP of AC and BC
P=`((6+9)/2,(1+4)/2)`
`(15/2,5/2)=((x+8)/2,(y+2)/2)`
`x+8=15`
`x=7`
`y+2=5`
`y=3`
D(7,3)
Area=`1/2(x_1(y_2-y_3)+x_2(y_3-y_1)+x_3(y_1-y_2)`
`=1/2(6(3-7/2)+7(7/2-1)+8(1-3))`
Area`=3/4unit^2`.