a square
no its only a right triangle not another one
A regular pentagon. (If it's not regular, then it could have a right angle, or even a few of them.)
A square is a regular shape. It will have four sides of equal length, and a right angle (90 degrees) in each corner.
A triangle can have a right angle, but it isn't regular if it does. Rectangles aren't regular, but have four right angles. Squares are regular quadrilaterals, and have four right angles. No other regular polygon has any right angles.
The equation for the size of an interior angle of an n-sided regular polygon is (n-2)180/n. When n=7, the interior angle of a regular sided shape would be 5x180/7 or approximately 128.57. The polygon in the question has an interior right angle (90 degree angle) and thus cannot be a regular shape. A 7 sided shape is called a heptagon. Thus, the shape described in the question is an irregular heptagon.
you cannot make a regular shape which has 3 right angles only, you will always end up with 4 right angles
A regular tetrahedron (an equilateral triangular pyramid).
Well, honey, that's a right triangle. It's like a regular triangle, but with a sassy little right angle thrown in there to keep things interesting. So, if you're looking for a shape that's all about that right angle life, you've found it.
a 3 sided shape is a right angle triangle
A right angle triangle
an angle with a acute and right angle
The only regular shape that has right angles is a square. A regular shape is one where all of its sides are the same length and all of its angles are the same angle. A right triangle is a notably non-regular shape with a right angle, but this is due to its simplicity and some useful mathematical facts about it. You could basically cut any corner off of a square and get a non-regular shape with right angles. If your cut is shallow enough, you will get a pentagon. If it's too deep, you just get a right triangle. You can keep cutting corners off (preserving the "right" one) to get a figure of any number of sides. It'll just look weird.