Question

A brick 4 cm by 4.5 cm by 9 cm is thrown in a bucket that contains some water. It is observed that the level of the water raises by 10 mm. What is the radius of the bucket? (ans 21.6 mm)

Answer 1

first find volume of the brick , vol of cuboid = lbh
volume of the brick = 4.5 * 9 * 4 = 162  $cm^{3}$

now if uh throw the brick into the  bucket , the volume of water raised in the bucket= volume of brick  ----(1)
raised height in bucket  = 10mm = 1 cm
volume of bucket = π$r^{2}$ h ( for h use raised height and find the radius )
volume of bucket = 3.14 *$r^{2}$* 1

as per (1)
 3.14 *$r^{2}$* 1 = 162$cm^{3}$
 $r^{2}$ = 162 / 3.14 = 51.6
r = √51.6 = 7.18 cm