Step 1:
\(a)
\Side of a cube is 30 cm.
\Error in measuring side of a square is 0.1 cm.
\ Let
be the side of the square.
Volume of the square
.
Apply derivative on each side.
\

Maximum possible error in the volume of the cube is
.
Relative error in the volume of the cube is 

Relative error in the volume of the cube is
.
Percentage error in the volume of the cube is 

Percentage error in the volume of the cube is
.
Step 2:
\(b)
\Surface area of the square
.
Apply derivative on each side.
\

Maximum possible error in the Surface area of the cube is
.
Relative error in the volume of the cube is 

Relative error in the Surface area of the cube is
.
Percentage error in the Surface area of the cube is 

Percentage error in the Surface area of the cube is
.
Solutions:
\(a)
\Maximum possible error in the volume of the cube is
.
Relative error in the volume of the cube is
.
Percentage error in the volume of the cube is
.
(b)
\Maximum possible error in the Surface area of the cube is
.
Relative error in the Surface area of the cube is 
Percentage error in the Surface area of the cube is
.