The pressure, P kilopascal (kPa), acting on a disc, of radius R cm, immersed in a liquid at a certain depth is directly proportional to the square of the radius of the disc.
When the disc has a radius of 5 cm, the pressure acting on it is 200 kPa.
If the radius of the disc is increased by 300%, find the percentage increase in the pressure acting on the disc.
(a) (i) Find a formula for P in terms of R.
(ii) Find the pressure acting on an immersed disc of radius 0.2 m.
(b) Disc A has a radius 80% greater than disc B.
Write down the ratio of the pressure acting on disc A to the pressure acting on disc B.​