Answer:
D A = (1/2) (y₂ - y₁)(x₃ - x₁)
Step-by-step explanation:
b = (y₂ - y₁)
h = (x₃ - x₁)
A = (1/2)bh
A = (1/2) (y₂ - y₁)(x₃ - x₁)