Question: TerraTrike is based in a city that is on the Grand River about thirty miles east of what?

Related documents: [0]  [DOC] TerraTrike is a brand of recumbent tadpole tricycles manufactured by WizWheelz Inc. TerraTrike is based in Grand Rapids, Michigan USA. TerraTrike's 2013 product line consists of 5 models: Rover, Rambler, Tour II, Sportster, Tandem Pro. Each model has 3 to 5 different component levels to meet each riders needs. [END] 
[1]  [DOC] Grand Rapids is the second-largest city in Michigan, and the largest city in West Michigan. It is on the Grand River about 30 mi east of Lake Michigan. As of the 2010 census, the city population was 188,040. In 2010, the Grand Rapids metropolitan area had a population of 1,005,648, and the combined statistical area of Grand Rapids-Muskegon-Holland had a population of 1,321,557. Grand Rapids is the county seat of Kent County. [END]  
Answer: Lake Michigan
Lake Michigan