使用.NET framework 3.5在C＃中调用Web API

I am trying to find the nearest store given a zip code. I came to know that yelp and foursquare provides the required APIs to do this. I am using .NET 3.5 framework. How do you make the http requests and handle the responses.Most of the solns on the web give it for .NET 4.5 onwards which includes the usage of HTTPClient class.I am trying to find the nearest store given a z