Send Geometry to query using ArcGIS REST API

The code below works for me.

using System;
using System.Text;
using System.Net;
using Newtonsoft.Json;
using System.IO;
using Newtonsoft.Json.Linq;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                string baseUrl = @"http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Specialty/ESRI_StateCityHighway_USA/MapServer";
                string jsonGeom = GetStateGeom(baseUrl,1, "Colorado");
                string featuresJson = QueryHighways(baseUrl, 0, jsonGeom);
                Console.WriteLine(featuresJson);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            Console.ReadLine();
        }

        private static string GetStateGeom(string baseUrl, int layerID,string state)
        {
            string url = String.Format("{0}/{1}/query?text={2}&f=pjson",baseUrl,layerID,state);

            var wc = new WebClient();
            var strm =  wc.OpenRead(new Uri(url));
            var strmReader = new StreamReader(strm);
            var json = strmReader.ReadToEnd();
            //Console.WriteLine(json);
            strm.Close();
            var jObj = JsonConvert.DeserializeObject(json) as JObject;
            JArray features = (JArray)jObj["features"];
            if (features.Count == 0)
            {
                Console.WriteLine("state of {0} not found", state);
                return null;
            }
            string jsonGeom = ((JObject)features[0])["geometry"].ToString();
            return jsonGeom;
        }

        private static string QueryHighways(string baseUrl, int layerID,string jsonGeom)
        {
            string url = String.Format("{0}/{1}/query", baseUrl, layerID);
            var wc = new WebClient();
            wc.Headers.Add("Content-Type", "application/x-www-form-urlencoded");
            StringBuilder sb = new StringBuilder();
            sb.Append("geometryType=esriGeometryPolygon");
            sb.Append(String.Format("&geometry={0}",jsonGeom));
            sb.Append("&inSR=&spatialRel=esriSpatialRelIntersects");
            sb.Append("&returnGeometry=true");
            sb.Append("&relationParam=");
            sb.Append("&where=");
            sb.Append("&returnCountOnly=false");
            sb.Append("&maxAllowableOffset=");
            sb.Append("&f=pjson");
            var bytes = Encoding.ASCII.GetBytes(sb.ToString());
            var respBytes = wc.UploadData(url, "POST", bytes);
            return Encoding.ASCII.GetString(respBytes);
        }
    }
}