Will they have to install a rest platform on their ramp?

Question

The city of Odessa, Texas is building a wheelchair ramp to make their courthouse accessible for persons in a wheel chair. The Americans with Disabilities Act (ADA) requires that a wheelchair ramp have an angle of elevation of 4.8°. The ADA guidelines also allow a maximum run of 30 feet of ramp before installing a rest platform. At the Odessa courthouse, the ramp must rise 2.5 feet to reach the top of the steps. Will they have to install a rest platform on their ramp?       

"Yes they will have to install a rest platform.", or "No they will not have to install a rest platform."      

Answer 1

using approximation sin angle = angle for small angle I arrive at a ramp length just short of 30 feet. However, as the contractor I would include the estimate for building the ramp as the measurement of the rise is only to two sig figs and rounding to the data results in 30 feet.

I get 29.9 feet using exact values for sin and pi

The platform is needed for the data given and reporting a conclusion to two sig figs.

But this begs the question do you know how to calculate the run if you have a rise and an angle?

If we stick to the sig figs for this problem being 2, then Odessa does need to build a rest platform as 29.9 rounds to 30 feet to two sig figs.

This points to a need for accuracy in our rise measurement of three sig figs...2.50 feet as my raw value is 29.875 then I can report 29.9 feet to the confidence in the accuracy of the rise and save Odessa a platform fee in the estimate. With that data no platform is needed.