To find a reasonable estimate, you would need to:
* Consult a reputable automotive website: Sites like Edmunds or Kelley Blue Book might have some specifications, but they likely won't give an exact angle of approach.
* Look at owner forums: Searching forums dedicated to the 2005 Chevrolet Suburban might reveal some user-reported measurements, but again, these would be estimates.
* Measure it yourself: The most accurate way would be to measure the angle using a protractor or angle finder.
Keep in mind that even with measurements, the angle will vary slightly depending on the specific trim level and any modifications made to the vehicle.