STEP 1

Equation of parabola : y^{2} = 8x

On comparing with : y^{2 }= 4ax , 4a = 8 , a = 2

STEP 2 :

P(x , 4) lies on parabola y^{2} = 8x & hence it must satisfy the equation of the parabola

∴ 4^{2} = 8x

x = 2 , P(2,4)

STEP 3 :

Focal distance of point

P(2,4) = PS

= PM ……….. FOCUS DIRECTRIX PROPERTY

= x + a

= 2 + 2 = 4 units