Question

Find the area of ${△}^2$ whose vertices are [-1, 0] [2, -3] & [2, -4].

Answer 1

Area $=\frac{1}{2}\left[x_1\right(y_2-y_3)+x_2(y_3-y_2)+x_3(y_1-y_2\left)\right]$

$=\frac{1}{2}[-1(-3+4)+2(-4-0)+2(0+3\left)\right]$

$=\frac{1}{2}[-1(1)=2(-4)+2(3\left)\right]$

$=\frac{1}{2}[-1-8+6]$

$=\frac{1}{2}(-3)$

$=\frac{-3}{2}$sq. units

${△}^2=\frac{9}{4}$ sq. units