Lines that meet at right angles are described as perpendicular to each other. Another word that describes lines that meet at right angles is orthogonal.
In two-dimensional plane geometry, whether or not two lines are perpendicular is determined by taking the product of the slopes. If the two lines are perpendicular, the product of the slopes is -1. For instance, a line with slope 5 is perpendicular to any line with slope -1/5. Any vertical line is defined as perpendicular to any horizontal line. This rule is necessary because the slope of a vertical line is undefined, and the slope of a horizontal line is zero.
Learn MorePerpendicular lines are lines that intersect one another at a 90 degree angle. If two lines are perpendicular, then multiplying the slopes of the two lines together equals -1.
Full Answer >One common example of perpendicular lines in real life is the point where two city roads intersect. When one road crosses another, the two streets join at right angles to each other and form a cross-type pattern. Perpendicular lines form 90-degree angles, or right angles, to each other on a two-dimensional plane.
Full Answer >Parallel lines are important in mathematics because they are at the base of several conjectures involving angles in geometry. Drawing a line, called a transversal, through a pair of parallel lines forms three different types of angles that have known mathematical properties.
Full Answer >The right angle congruence theorem posits that right angles are always congruent to one another. A right angle is an angle that makes a 1/4-turn of a circle and is measured at 90 degrees.
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