Final answer:
The unknown quantity corresponds to 43.2 centimeters when 18 inches are scaled up by the given ratio of 2.4 centimeters per 1 inch.
Step-by-step explanation:
To scale the ratio and determine the unknown quantity, we set up a proportion. Given the ratio 2.4 centimeters per 1 inch, we need to find the equivalent number of centimeters for 18 inches. The proportion looks like this:
2.4 cm / 1 inch = x cm / 18 inches
We can solve for 'x' by cross-multiplying and dividing to find the number of centimeters that correspond to 18 inches. Multiply both sides by 18 inches to isolate 'x' on one side of the equation:
x cm = 2.4 cm * 18
Next, we calculate the product:
x = 43.2 cm
So, 18 inches correspond to 43.2 centimeters when scaled up by the given ratio.