Find values of K, if the area of a triangle is 4 square units whose vertices are
(– 2,0), (0, 4) and (0, k)
Given: – Vertices of triangle are (– 2,0), (0, 4) and (0, k) and the area of the triangle is 4 sq. units.
Tip: – If vertices of a triangle are (x1,y1), (x2,y2) and (x3,y3), then the area of the triangle is given by:
Now,
Substituting given value in above formula
⇒
Removing modulus
⇒
Expanding along R1
⇒
⇒ [ – 2(4 – k) – 0(0) + 1(0 – 0)] = ±8
⇒ – 8 + 2k = ± 8
Taking + ve sign, we get
⇒ 8 = – 8 + 2k
⇒ 2k = 16
⇒ k = 8
Taking – ve sign, we get
⇒ – 8 = 2x – 8
⇒ 2k = 0
⇒ k = 0
Thus k = 0, 8