Answer 1

Here, A(x₁, y₁) ≡ A(0, 5), B(x₂, y₂) ≡ B(0, – 5), C(x₃, y₃) ≡ C(5, 0)

Area of a triangle = `1/2|(x_1, y_1, 1),(x_2, y_2, 1),(x_3, y_3, 1)|`

∴ A(ΔABC) = `1/2|(0, 5, 1),(0, -5, 1),(5, 0, 1)|`

= `1/2[0(-5 - 0) - 5(0 - 5) + 1(0 + 25)]`

= `1/2(0 + 25 + 25)`

= `50/2`
∴ A(ΔABC) = 25 sq. units