GEO006 · Geometry basics · Classes 6–10
Perpendicular lines
Perpendicular lines meet at a right angle (90°). On a graph, the product of their slopes is −1.
⊥Perpendicular lines
📐 Formula
m₁ × m₂ = −1, so m₂ = −1/m₁
✏️ Worked example
y = 2x is perpendicular to y = −½x, because 2 × (−½) = −1.
🌍 Where it is used
Walls and floors, the corners of paper, street grids.
❓ Quick check
Slope perpendicular to 3?
🏋️ Practice
EasySlope perpendicular to −2?
Answer: ½
MediumAre y = x and y = −x perpendicular?
Answer: Yes
ChallengeLine through the origin perpendicular to y = 4x + 1?
Answer: y = −¼x