adjecent basically means "next to" and perpindicular is meeting at an right angle (90 degrees) so squares have them and right angle triangles do to.
"Adjacent" means next to each other. "Perpendicular" means at an angle of 90 degrees. Rectangles (this includes squares) have adjacent perpendicular sides. So do right triangles.
Perpendicular adjacent sides in a triangle refer to the two sides that form a right angle. In a right triangle, these sides are next to each other and are crucial for applying the Pythagorean theorem. This relationship is important in solving many geometric problems involving right triangles.
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