The new iPhone 6 Plus has a perimeter of 471.8 millimeters. The height of the new phone is 2.5 millimeters more than twice its width. Find the...

The new iPhone 6 Plus has a perimeter of 471.8 millimeters. The height of the new phone is 2.5 millimeters more than twice its width. Find the dimensions of the new phone.  Please set up and solve this problem following the steps below:

a) Define the unknown quantities in terms of one variable. b) Translate the question into an equation. c) Solve the equation, showing all work including appropriate units.