CBSE Class 12 Sample Paper for 2021 Boards

Class 12
Solutions of Sample Papers and Past Year Papers - for Class 12 Boards

Find the area of the triangle whose two sides are represented by the vectors 2iΒ Μ πππ β 3jΒ Μ.

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Question 11 Find the area of the triangle whose two sides are represented by the vectors 2π Μ πππ β3π Μ We know that Area of triangle ABC = 1/2 |(π΄π΅) β Γ (π΄πΆ) β | Here, (π΄π΅) β = 2π Μ and (π΄πΆ) β = β3π Μ (π¨π©) β Γ (π¨πͺ) β = |β 8(π Μ&π Μ&π Μ@2&0&0@0&β3&0)| = π Μ [(0 Γ 0)β(β3 Γ 0)] β π Μ[(2 Γ 0)β(0 Γ 0)] + π Μ[(2 Γ β3)β(0 Γ 0)] = β6π Μ Magnitude of (π΄π΅) β Γ (π΄πΆ) β = |β6π Μ| = 6 So, area of triangle ABC = 1/2 |(π΄π΅) β" Γ " (π΄πΆ) β | = 1/2 Γ 6 = 3 square units