You read online that a 15 ft by 20 ft brick patio would cost about $2,275 to have professionally installed. Estimate the cost of having a 23 by 28 ft brick patio installed.

Answer 1

A patio that is 15 ft by 20 ft covers 300 sq ft. (length times width)

For a patio that is 23 ft by 28 ft the square footage is 644 sq ft.

Set up a proportion to find out the cost of the 2nd patio.

$2275/300 ft² = $x / 644 ft² (2275 dollars it to 300 sq ft as unknown $ is to 644 sq ft)

Solve the proportion by cross multiplying (product of the extremes equals product of the means)

An easier way to do it is to just multiply both sides of the equation by 644 ft² to isolate $x.

$x = $2275(644 ft²)/300 ft² (notice that the units ft² cancel out and we are left with dollars)

Using a calculator or performing the above computation manually results in: $4883.67. That is more than twice as much, but that makes sense because 644 is more than twice 300.