Not tested but: width and height are the width and height of the shape. They are in this example in km. centerLat and centerLon are the lat and long of the shape (you have it in the Location property).
First convert the units (km) to nautical miles. Then as this example show it is easy to calculate the left top coordinates of the shape. The 3 other you can find yourself I gues. If you need help just ask If your units are in miles then 1 mile == 1.6093 km.
The reason for the nautical miles is because 1 nautical mile is exact 1 minute of the earth circle. So easy to use in the calculations.
the Cosinus is neede to correct the longitude because lat==long only on equater.
Code:double nauticalMilesHeight = height / 1.852; // heigth and width are in km double nauticalMilesWidth = width / 1.852; // so we convert to nautical miles double leftTopLat = centerLat + nauticalMilesHeight / 2 / 60; double leftTopLon = centerLon - nauticalMilesWidth / 2 / 60 / Math.Cos(centerLat);