Last updated at May 29, 2018 by Teachoo

Transcript

Example 24 Find the area of a triangle having the points A(1, 1, 1), B(1, 2, 3) and C(2, 3, 1) as its vertices. A (1, 1, 1) , B (1, 2, 3) ,C (2, 3, 1) The area of triangle ABC is 12 𝐴𝐵× 𝐴𝐶 𝑨𝑩 × 𝑨𝑪 = 𝑖 𝑗 𝑘012120 = 𝑖 1×0−(2×2) − 𝑗 0×0−(1×2) + 𝑘 0×2−(1×1) = −4 𝒊 + 2 𝒋 – 1 𝒌 Magnitude of 𝐴𝐵 × 𝐴𝐶 = −42+22+ −12 𝐴𝐵 × 𝐴𝐶 = 16+4+1 = 21 So, area of triangle ABC = 12 𝐴𝐵 × 𝐴𝐶 = 12 × 21 = 212 Therefore, the required area is 𝟐𝟏𝟐

Examples

Example 1

Example 2

Example 3

Example 4

Example 5

Example 6

Example 7

Example 8

Example 9

Example 10

Example 11

Example 12

Example 13

Example 14 Important

Example 15

Example 16 Important

Example 17

Example 18

Example 19

Example 20

Example 21 Important

Example 22

Example 23 Important

Example 24 Important You are here

Example 25 Important

Example 26

Example 27

Example 28 Important

Example 29 Important

Example 30 Important

Example 26 (Supplementary NCERT)

Example 27 (Supplementary NCERT)

Example 28 (Supplementary NCERT)

Example 29 (Supplementary NCERT)

Example 30 (Supplementary NCERT)

Example 31 (Supplementary NCERT)

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.