<u>Answer:
</u>
825 feet of area of the wall required to be painted.
<u>Explanation:
</u>
Given:
Length of the room = 15 feet
Width of the room =12 feet
Height of the room = 9-foot
Size of the door= 3 feet x 7 feet
To find:
The area of the walls that requirespainted=?
Solution:
We know that,
Area of walls that need paint = total surface area of room – area of door that doesn’t need paint…………(1)
Finding the Total area of the room:
room is cuboidal shape,
Then, its total surface area = 2(lb + bh + hl)
Where
h is height,
l is length,
b is width
Substituting the values,
Total surface area = 2(15 x 12 + 12 5 9 + 9 x 15)
Total surface area = 2(180+108+135)
Total surface area = 2( 423)
Total surface area = = 846 feet…………..(2)
Finding the area of the door:
Area of door = area of rectangle = length x width
Substituting the values,
area of door= 3 x 7 = 21 feet……………(3)
Substituting (2) and (3) in (1)
Area that is require paint = 846 – 21 = 825 feet
