Answer:
The dimensions are:
Length = 5m and Width = 4m
Or
Length = 4m and Width = 5m
Step-by-step explanation:
A rectangular dining room has an area of 20 square meters. It's perimeter is 18 meters. What are the dimensions of the dining room?
Area of a rectangle = Length × Width
= LW = 20 m²
Perimeter of a rectangle =
2L + 2W = 18 m
Hence:
LW = 20...... Equation 1
L = 20/W
2L + 2W = 18 ...... Equation 2
We substitute
20/W for L in Equation 2
2(20/W) + 2W = 18
40/W + 2W = 18
Multiply through by W
40 + 2W² = 18W
2W² - 18W + 40 = 0
2W² - 10W - 8W + 40 = 0
(2W - 8 )(W - 5) = 0
2W - 8 = 0
2W = 8 , W = 8/2 = 4m
W - 5 = 0
W = 5m
W = 4m or 5 m
Solving for L
When W = 5 m
L = 20/W
L = 20/5
L = 4m
When W = 4m
L = 20/W
L = 20/4
L = 5m
Therefore, the dimensions are:
Length = 5m and Width = 4m
Or
Length = 4m and Width = 5m
