Right angles are used in architecture. All buildings are essentially based off of right angles (from the ground to a wall).
A triangle-based pyramid has one right angle at the apex where the three triangular faces meet. This right angle is formed by the intersection of the base of the pyramid and one of its slant edges. The other angles in a triangle-based pyramid are typically acute angles formed by the base and the slant edges.
4
Normally four but there could be six if the opposite edges at the apex met at right angles.
No angles are larger than 90 degrees in a square based pyramid.
Yes its base contains 4 corner right angles
Yes - it has four around the base !
4
Not normally if it's a regular based pentagonal pyramid.
Acute, right angle, obtuse and reflex.
There are no right angles in a square based pyramid, so Pythagoras and his theorem are not involved.
... right angles, by definition of a rectangle.... right angles, by definition of a rectangle.... right angles, by definition of a rectangle.... right angles, by definition of a rectangle.