Question

The vertices of a ΔABC are A(3, 8), B(–1, 2) and C(6, –6). Find: 
(i) Slope of BC
(ii) Equation of a line perpendicular to BC and passing through A.

Answer 1

A (3, 8) , B(–1, 2) , C(6, –6)

(i) Slope of BC = `(y_2 - y_1) /(x_2- x_1) = (-6 - 2)/(6-(-1)) = (-8)/7` 

∴ Slope of BC  = - `8/7`

(ii) Slope of line perpendicular to BC `= (-1)/((-8/7)) = 7/8`

Required line ⇒ y - y₁ = m(x - x₁ ) 

                        y - 8 = `7/8 (x-3)`

                      `8y - 64 = 7x -21`

                     `7x - 8y + 43 = 0`