Which shape has all sides of equal length and equal angles?

The shape that has all sides of equal length and equal angles is a square. A square is a specific type of rectangle where not only are the opposite sides equal in length (which is a property of all rectangles), but all four sides are also equal. Additionally, all interior angles in a square are right angles, measuring 90 degrees, making the angles equal as well.

In contrast, while rectangles have equal opposite sides and equal angles, their adjacent sides can differ in length. A triangle can have equal sides and angles if it is specifically an equilateral triangle, but that does not apply to all triangles. A pentagon can have equal sides and angles (specifically a regular pentagon), but it does not inherently possess this property like a square does. Thus, the square uniquely meets the criteria of having all sides and angles equal.