diket: garis a⊥ garis b jika gradien garis a = -2/3 maka tentukan gradien garis b! -2/3 maksudnya min 2 per 3

ma . mb = -1
-2/3 . mb = -1
mb = -1 : -2/3
mb = -1 . 3/-2
mb = -3/-2
mb = 3/2
keterangan
. = kali
ma = gradien a
mb = gradien b