Find the distance

We know the distance formula from a point (0,0) to a straight line is $d=\frac { ∣C∣ }{ \sqrt { { A }^{ 2 }+{ B }^{ 2 } } }$ .
Here the equation of straight line $y=mx+c$ . where $m=\frac { 4 }{ 3 }$ .
again from the slope we can tell, when the straight line moves 3' horizontally it moves 4' vertically. so when the line moves 30' horizontally it moves 40' vertically. so c becomes 40+20=60'.
therefore $y=(4/3)x +60$ or $4x-3y+180=0$ .
so the distance $d=\frac { 180 }{ \sqrt { { 4 }^{ 2 }+{ 3 }^{ 2 } } } = \frac {180 }{ 5 } = 36.$
so, d=36'