7.3 1(ii)

(ii) (-5, -1) (3, -5) (5, 2)

हल – माना

A(-5, -1)

B(3, -5)

C(5, 2)

यहाँ

x₁ = -5,   y₁ = -1

x₂ = 3,   y₂ = -5

x₃ = 5,   y₃ = 2

∴ Δ ABC का क्षेत्रफल 

= ½ [x₁(y₂ – y₃) + x₂(y₃ – y₁) + x₃(y₁ – y₂)]

= ½ [ -5(-5 – 2) + 3(2 + 1) + 5(-1 + 5)]

= ½ [ -5(-7) + 3(3) + 5(4)]

= ½ [ 35 + 9 + 20]

= ½ [ 64 ]

= 32 वर्ग इकाई