Shortcut Trick
Midpoint of the line connecting (2, 8) and (6, 4) is ((2 + 6) ÷ 2, (8 + 4) ÷ 2) = (4, 6).
Slope of the given line segment = (4 − 8) ÷ (6 − 2) = −4 ÷ 4 = −1.
Slope of its perpendicular bisector = −1 ÷ (−1) = 1.
Equation of the bisector passing through (4, 6) with slope 1: y − 6 = 1 × (x − 4).
Simplifying the equation gives: y = x + 2.
∴ The correct answer is y = x + 2.
Alternate Method
Given:
Two points: A(2, 8) and B(6, 4)
Formula Used:
Midpoint formula: M = ((x1 + x2) ÷ 2, (y1 + y2) ÷ 2)
Slope formula: m = (y2 − y1) ÷ (x2 − x1)
Perpendicular slope condition: m1 × m2 = −1
Equation of a straight line: y − y1 = m × (x − x1)
A (2, 8)
B (6, 4)
M (4, 6)
y = x + 2
Calculation:
⇒ Let the line segment be AB. The perpendicular bisector passes exactly through the midpoint M of AB.
⇒ Midpoint M = ((2 + 6) ÷ 2, (8 + 4) ÷ 2)
⇒ M = (8 ÷ 2, 12 ÷ 2) = (4, 6)
⇒ Slope of line AB (m1) = (4 − 8) ÷ (6 − 2)
⇒ m1 = −4 ÷ 4 = −1
⇒ Let the slope of the perpendicular bisector be m2.
⇒ m1 × m2 = −1
⇒ −1 × m2 = −1 ⇒ m2 = 1
⇒ Now, substitute the point M(4, 6) and slope m2 = 1 into the straight line equation.
⇒ y − 6 = 1 × (x − 4)
⇒ y − 6 = x − 4
⇒ y = x − 4 + 6
⇒ y = x + 2
∴ The correct answer is y = x + 2.
Additional Information
Distance Formula
The linear distance between two points (x1, y1) and (x2, y2) on a Cartesian plane is given by D = √((x2 − x1)2 + (y2 − y1)2).
Section Formula
The coordinates of a point dividing a line segment internally in the ratio m:n are calculated as ((m×x2 + n×x1) ÷ (m+n), (m×y2 + n×y1) ÷ (m+n)).
Parallel and Perpendicular Lines
Two lines are parallel if their slopes are strictly equal (m1 = m2). Two lines are exactly perpendicular if the product of their respective slopes is negative one (m1 × m2 = −1).