Answer:
$3028
Explanation:
A 15ft by 20ft brick patio would cost about $2,275 to have professionally installed.
[tex]\begin{gathered} \text{Area of the patio}=15\times20 \\ =300ft^2 \end{gathered}[/tex]Therefore, the unit cost (cost per ft²) will be:
[tex]=\frac{\$2275}{300ft^2}\text{ }[/tex]If the dimension of the new patio is 19ft by 21ft
[tex]\begin{gathered} \text{Area of the new patio=}19\times21 \\ =399ft^2 \end{gathered}[/tex]Therefore, the estimated cost will be:
[tex]\begin{gathered} =\frac{\$2275}{300ft^2}\times399ft^2 \\ =\$3025.75 \\ =\$3028\text{ (to the nearest dollar)} \end{gathered}[/tex]