Grade 7 - Mathematics 9.42 Area of the Four Walls of a Room - II

Example:
The perimeter of the floor is 115 metres and the height of the room is 16 metres, find the area of the room and find the cost of painting the four walls at the rate of $620 for 100 square metres.

Solution:
Given that,
Perimeter of the floor = 115 metres.
Height = 16 metres.
Therefore, total area of the four walls A = ph.
ie A = 115 * 16
= 1840 Square metres.
Therefore, total area of the four walls is 1840 square metres.
Cost of the painting the four walls = $ (620 * 1840) / 100
= $ 11,408.

Directions: Read the above example carefully and answer the following questions:

If the perimeter of a floor is 12x units and the height of the room is x units, find the area of the floor. Also find the area when x = 5 metres.
(Answer: 12x^{2}; 60 square metres)