The geometric answer is a rectangle but that does not have 13 letters. The answer is NOT a quadrilateral nor parallelogram because neither of them need have 4 right angles.
right angles and straight angles
No, there is only 1 set of parallel lines in the letter M.
right (90˚) and 180˚ angles
There are no right angles in the letter "e".
In the upper-case letter A? I see none, nor in lower case a either.
When two parallel lines are intersected by a transverse line, they form eight angles. You can consider the parallel lines as the horizontal lines of the letter Z and the transversal as the sloped line of Z. Then the two angles in that Z-shape are the Z angles. The transversal for Z-angles can slope either way. It can be proved that Z-angles, properly called ALTERNATE angles, are equal.
_\_________ .a\b _c\d________ .....\ When a line crosses 2 lines, 8 angles are formed. Four are exterior angles - outside the 2 lines, and four are interior angles. These are labelled a, b, c, d in the diagram. a & d are alternate interior angles because they alternate from one side of the intersecting line to the other; b & c are also alternate interior angles. They are also known as "Z-angles" because the top parallel line, the transversal and the bottom parallel line which define the two angles for the letter Z (or a distorted version of it). If angle a = angle d (in which case angle b = angle c as well), the 2 lines drawn horizontally are parallel. If alternate interior angles are equal, the 2 lines are parallel. OR If you know the lines are parallel, then alternate interior angles must be equal. Not the greatest diagram; please ignore the ... but even a lousy diagram helps. And no, you don't use lower case letters for angles but there shouldn't be any confusion.
13 = thirteen.
A thirteen letter word that ends with tending: overextending
There are 3 acute angles and 2 obtuse angles in the letter A.
What is a thirteen letter word for the French and Indian Revolution?
The letter "i" in "thirteen" is not silent.
The letter "K"
As a capital letter M it has three angles
stabilization
appropriately
The letter 'W' has three acute angles.