)a room measures 15 feet long and 12 feet wide, with a 9-foot ceiling. there is a single doorway in one wall that measures 3 feet × 7 feet that does not get painted. what is the area of the walls that requires paint?

825 feet of area of the wall  required to be  painted.

Explanation:

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

step by step explanation: when u removing the parentheses and combined them that would be : x+3y-x-y=2y

step-by-step explanation: