Everything Maths Grade 10

SOLUTION

Step 1: Calculate the original volume and surface area

V=lbh

= 3 3  4

=36 cm^3

A= 2 [(lh) + (lb) + (bh)]

= 2 [(34) + (33) + (34)]

=66 cm^2

Step 2: Calculate the new volume and surface area

Two of the dimensions are multiplied by a factor of 3.

Vn= 3l 3 bh

= 3(3)3(3) 4

=324 cm^3

An= 2 [(3lh) + (3l 3 b) + (3bh)]

= 2 [(3(3)4) + (3(3)3(3)) + (3(3)4)]

=306 cm^2

Step 3: Express the new dimensions as a factor of the original dimensions

V= 36

Vn= 324

Vn

V

=

324

36

= 9

)Vn= 9V

= 3^2 V

A= 66

An= 306

An

A

=

306

66

)An=

306

66

A

=

51

11

A

Chapter 13. Measurements 453