Three sides AB, BC and CA of a triangle ABC are 5x – 3y + 2 = 0, x – 3y – 2 = 0 and x + y – 6 = 0 respectively. Find the equation of the altitude through the vertex A.
Given:
The sides AB, BC and CA of a triangle ABC are as follows:
5x − 3y + 2 = 0 … (1)
x − 3y − 2 = 0 … (2)
x + y − 6 = 0 … (3)
To find:
The equation of the Altitude through the vertex A.
Concept Used:
Point of intersection of two lines.
Explanation:
Solving (1) and (3):
x = 2 , y = 4
Thus, AB and CA intersect at A (2, 4).
Let AD be the altitude.
AD⊥BC
∴ Slope of AD × Slope of BC = −1
Here, slope of BC = slope of the line (2) = 1/3
∴ Slope of AD×1/3 = - 1 ⇒ Slope of AD = - 3
Hence, the equation of the altitude AD passing through A (2, 4) and having slope −3 is y - 4 = - 3x - 2⇒ 3x + y = 10