Suppose a city has 810 high-rise buildings, and 29 of these buildings have rooftop gardens. find the percentage of high-rise buildings with rooftop gardens in this city. round your answer to the nearest tenth of a percent.

For this case we can make the following rule of three:
 810 > 100%
 29 > x
 From here, we clear the value of x.
 We have then:
 x = (29/810) * (100)
 x = 3.580246914%
 Round to the nearest tenth of a percent:
 x = 3.6%
 
 The percentage of high-rise buildings with rooftop gardens in this city is:
 x = 3.6%