There is only one regular polygon which contains right angles - this is a square. None of the other regular polygons from 3 sides and upwards has a right angle.
The longest side is always opposite the right angle so the sides of the right angle are 3 and 4 units.
It is a right angle triangle
Providing that it is a regular polygon it will have 8 sides.
No because a quadrilateral has 4 sides whereas a triangle has 3 sides.
Angle
A triangle.
A right triangle has three sides and one right angle.
A right angle triangle.
3 : 4 : 5
An equilateral triangle has 3 equal sides, and each angle is 60 degrees.
A triangle has 3 sides and 3 inside angle that add up to 180 degrees