Find the area of a triangle with vertices 11 02 30SolutionTh

Find the area of a triangle with vertices (-1,-1), (0,2), (3,0).

Solution

The area of a triangle formed by joining the points (x₁, y₁), (x₂, y₂) and (x₃, y₃) is

½ |y₁ (x₂ - x₃) + y₂ (x₃ - x₁) + y₃ (x₁ - x₂)| sq. units

(x1,y1) = (-1,-1) and (x2,y2)=(0,2) and (x3,y3) =(3,0)

area = 1/2 | -1(0-3) + 2(3-(-1) ) + 0 (-1 -0) |

= 1/2 | -1(-3) + 2 (3+1) + 0 |

=1/2 | 3 +2(4) |

= 1/2 | 3 +8|

= 1/2 |11|

= 11/2 sq units