How many pairs of perpendicular lines are there in the diagram?
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How many pairs of perpendicular lines are there in the diagram?
Remember that perpendicular lines are vertical lines that form a right angle of 90 degrees between them.
The right angle we have in the drawing is angle ABC.
The lines that form the angle ABC are AB and BC.
Since we have one marked angle in the triangle, we must have a pair of perpendicular lines.
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Determine which lines are parallel to one another?
Look for right angle markers (small squares) at the intersection point, or check if the angle measures exactly . In this diagram, the small square at point B shows that lines AB and BC are perpendicular.
A pair means two lines that intersect perpendicularly. Even if you see 3 lines, you might only have 1 perpendicular pair. Always ask: which two lines form a right angle together?
In a flat (2D) diagram, no. You can have at most one pair of perpendicular lines meeting at any point. Three mutually perpendicular lines only exist in 3D space.
Look carefully at the intersection angles. If an angle appears to be exactly (like a perfect corner), the lines are likely perpendicular. However, marked right angles are the most reliable indicator.
Count the pairs of perpendicular lines: AB and BC form one right angle at point B. Even though there are 3 line segments total (AB, BC, AC), only one pair is perpendicular to each other.
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