â¢ equilateral - all 3 sides are equal. 2) By the types of angles they have: â¢ acute triangle - all 3 angles are acute (less than 90Â°) â¢ right triangle - has one right angle (a right angle = 90Â°) â¢ obtuse triangle - has one obtuse angle (an obtuse angle is greater than 90Â° and less than 180Â°).
Over the last 30 years, the time frame for the carving of the Grand Canyon has gone full circle. Thirty years ago, most evolutionists believed the canyon was about 70 million years old. But that estimate changed as radioisotope dating was utilized to show the plateau to be much older than the canyon itself.
For years, scientists thought the Grand Canyon was 5 million to 6 million years old. More recent studies, though, show that it may be as much as 17 million years old. The park is a treasure trove for geologists and archaeologists.Grand Canyon National Park has recorded more than 4,800 archaeological resources in a study of just 3 percent of the parkâs area. The oldest human artifacts that have been found are about 12,000 years old and appear to be from the Paleo-Indian time period.or years, scientists thought the Grand Canyon was 5 million to 6 million years old. More recent studies, though, show that it may be as much as 17 million years old. The park is a treasure trove for geologists and archaeologists.