Perpendicular Lines (Leaving Cert Mathematics): Flashcards

Right angle ($90$°)

$m_1 \times m_2 = -1$

$m_2 = -\frac{1}{m_1}$

Vertical line $x = k$

Undefined

$0$

$y - y_1 = m(x - x_1)$

Find negative reciprocal of given slope

Check if $m_1 \times m_2 = -1$

$-\frac{1}{2}$

$\frac{1}{3}$