Question

Calculate the lower and upper bound for the perimeter of a rectangle whose lenght and width are 6.8 cm and 4.2 cm correxted to 1 decimals place

Answer 1

1)  Length of Perimeter = 6.8 cm correct to one decimal place
    The lower and upper bound of this measurement are:
     6.75  -----------------     6.8   ------------------------------        6.85
lower bound             actual measurement                   upper bound
Therefore, lower and upper bounds of length are 6.75 cm and 6.85cm. respectively.

2)  Width of Perimeter = 4.2 cm correct to one decimal place
     The lower and upper bound of this measurement are:
     4.15  -----------------     4.2   ------------------------------        4.25
lower bound             actual measurement                  upper bound

Therefore, lower and upper bounds of width are 4.15 cm and 4.25 cm. respectively.

Upper bound for the Perimeter  = 2(upper bound of length)+2(upper  
                                                         bound of width)
                                                      = 2 X 6.85 + 2X 4.25
                                                      = 13.7 cm +  8.5 cm = 22.2 cm

Lower bound for the Perimeter= 2(lower bound of length)+2(lower 
                                                       bound of width)
                                                    = 2 X 6.75 + 2X 4.15
                                                    = 13.5 cm + 8.3 cm = 21.8 cm

Therefore, the upper and lower bounds of the Perimeter are 22.2 cm and 21.8 cm respectively.

Answer 2

Answer:

Lower bound :- 21.8 cm

Upper bound :- 22.2 cm

Step-by-step explanation:

The perimeter of rectangle formula :-  2(Length + Width)

The length of the rectangle is :

6.8 lies in 6.75 ≤  x < 6.85

The width of the rectangle is :

4.2 lies in 4.15 ≤ x < 4.25

Lower bound of the perimeter is :

2(6.75+4.15) = 21.8 cm

The upper bound if the perimeter is :

2(6.85+4.25) = 22.2 cm

Hope this helps you !