Question

Find values of k if area of triangle is 4 sq. units and vertices are (−2, 0), (0, 4), (0, k).

Answer 1

Area of triangle = 4 sq. units

Again, area of triangle = `1/2 |(-2,0,1),(0,4,1),(0, k,1)|`

= `1/2 [-2|(4,1),(k,1)| - 0|(0,1),(0,1)| + 1|(0,4),(0,k)|]`

= `1/2 [-2 (4 - k) - 0 (0 - 0) + 1 (0 - 0)]`

= `1/2 xx (-2) (4 - k)`

= k − 4

Now, k − 4 = ±4

⇒ k − 4 = −4 or k − 4 = 4

⇒ k = 0, 8