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.
How The Grand Canyon Was Formed: Anomaly Gives New Clues. Just how the Grand Canyon was formed has been hotly debated by scientists and tourists alike almost since its discovery. But new evidence has potentially shed light on the gigantic canyon's origins, according to LiveScience.