Kyle's rate is 18 miles / 112.5 minutes, which simplifies to 0.16 miles per minute.
To complete a 26.2-mile marathon at this rate, we can set up a proportion:
18 miles / 112.5 minutes = 26.2 miles / x minutes
Cross-multiplying:
18 miles * x minutes = 112.5 minutes * 26.2 miles
Simplifying:
x = (112.5 minutes * 26.2 miles) / 18 miles
x = 165.625 minutes
Therefore, it will take Kyle 165.625 minutes, or about 2 hours and 46 minutes, to complete the marathon.