They are equal.
Complementary.
Complementary
Complementary
Yes. If the two acute angles have their measures add up to 90 degrees, and both angles share one side that is common to each angle (they are adjacent), then their non-common sides will be perpendicular.
No. This is only true of squares and rectangles. Perpendicular means that the sides meet in a right angle. A rhombus has two acute angles and two obtuse angles.
No sides perpendicular means no right angles. A rhombus is a quadrilateral with no right angles so no sides perpendicular.
The word acute refers to angles, not sides. It does have all three angles are acute (less than 90°)
It could be a trapezoid having 2 right angles, an obtuse angle and an acute angle
Sides aren't acute, angles are. A triangle with three acute angles would be called (appropriately enough) an acute triangle.
If the figure has only four sides all together, then it's not possible for all four angles to be acute.
no, they have congruent angles
Not normally but as a rectangle it has perpendicular sides that meet at right angles