JEE Main · Mathematics ↓ Falling

Straight Lines appeared 29 times across 3 years — 3.4% of Mathematics. This question is from Orthocenter and Concurrency.

Year 2026 2025 2024 Total
Questions 7 13 9 29

Among the statements: (S1): If A(5,-1) and B(-2,3) are two vertices of a triangle, whose orthocentre is (0,0), then its third vertex is (-4,-7) and (S2): If positive numbers 2a, b, c are three consecutive terms of an A.P., then the lines ax + by + c = 0 are concurrent at (2,-2).

Solution & Explanation

Related Formula

Orthocenter property: Altitude from A is perpendicular to BC, Altitude from B is perpendicular to AC. Concurrency of lines: ax+by+c=0 passes through (x₀, y₀) if ax₀+by₀+c=0 holds.

Core Logic

Triangle orthocenter diagram for Q7 - JEE Main 2026 Evening
Triangle orthocenter diagram for Q7 - JEE Main 2026 Evening

Statement 1: Let third vertex be C(h,k) and orthocenter O(0,0).

  • Slope AO · Slope BC = -1 ((-1)/(5)) · ((k-3)/(h+2)) = -1 5h - k + 13 = 0
  • Slope BO · Slope AC = -1 ((3)/(-2)) · ((k+1)/(h-5)) = -1 4k = 7h
  • Solving simultaneously gives h = -4, k = -7 C(-4,-7). Statement 1 is correct.

    Statement 2: 2a, b, c in A.P. 2b = 2a + c 2a - 2b + c = 0. Comparing with ax + by + c = 0 gives x = 2, y = -2. Statement 2 is correct.

Step 1: Final Conclusion

Both (S1) and (S2) are correct statements.

Pattern Recognition

Orthocenter coordinates yield perpendicularity conditions via slopes. Concurrency follows directly from linear relation between line coefficients.

Chapter Mix

Class 11 Maths: Straight Lines

Reference Study Guides

More Straight Lines Previous-Year Questions — Page 6

Q1 jee_main_2024_30_jan_morning Rotation of Axes and Lines
A line passing through the point A(9,0) makes an angle of 30° with the positive direction of x-axis. If this line is rotated about A through an angle of 15° in the clockwise direction, then its equation in the new position is
  • A. y√(3) - 2 + x = 9
  • B. x√(3) - 2 + y = 9
  • C. x√(3) + 2 + y = 9
  • D. y√(3) + 2 + x = 9

Solution

Related Formula
y - y₁ = (θ)(x - x₁)
Core Logic

Rotation of Axes and Lines diagram for Q1 - JEE Main 2024 Morning
Rotation of Axes and Lines diagram for Q1 - JEE Main 2024 Morning

The initial line makes an angle of 30° with the positive x-axis. It is rotated clockwise by 15° about the point A(9, 0). The new angle made by the line with the positive direction of the x-axis is 30° - 15° = 15°.

Step 1: Equation of the new line

The equation of the line passing through A(9, 0) with a slope of 15° is:

Eqⁿ: y - 0 = 15° (x - 9)

We know that 15° = 2 - √(3).

y = (2 - √(3)) (x - 9)
Step 2: Rearranging to match options

Dividing by (2 - √(3)):

y2 - √(3) = x - 9

Notice that 2 - √(3) = -(√(3) - 2). Thus:

-y√(3) - 2 = x - 9 y√(3) - 2 + x = 9
Pattern Recognition

A clockwise rotation decreases the angle of inclination. Calculate the new angle, find its tangent, and carefully algebraicize the denominator to match the given option forms.

Chapter Mix

Class 11 Maths: Straight Lines

Q2 jee_main_2024_31_jan_evening Centroid and Orthocentre
Let A (a, b), B(3, 4) and (-6, -8) respectively denote the centroid, circumcentre and orthocentre of a triangle. Then, the distance of the point P(2a + 3, 7b + 5) from the line 2x + 3y - 4 = 0 measured parallel to the line x - 2y - 1 = 0 is
  • A. 15 √(5)7
  • B. 17√(5)6
  • C. 17 √(5)7
  • D. √(5)17

Solution

Related Formula
Centroid divides the line joining Orthocentre and Circumcentre in 2:1

Distance in parametric form: x = x₁ + r θ, y = y₁ + r θ

Core Logic

Centroid and Orthocentre diagram for Q2 - JEE Main 2024 Evening
Centroid and Orthocentre diagram for Q2 - JEE Main 2024 Evening

Let Orthocentre C(-6, -8) and Circumcentre B(3, 4). Centroid A(a, b) divides CB in 2:1.

a = (2(3) + 1(-6))/(2+1) = 0 b = (2(4) + 1(-8))/(2+1) = 0

So, P(2a+3, 7b+5) = (3, 5).

The line along which distance is measured is parallel to x - 2y - 1 = 0, giving slope m = θ = (1)/(2). Using parametric coordinates from P(3,5):

x = 3 + r θ, y = 5 + r θ

Substitute into the target line 2x + 3y - 4 = 0:

2(3 + r θ) + 3(5 + r θ) - 4 = 0 r(2 θ + 3 θ) = -17

From θ = 1/2, we get θ = 1√(5) and θ = 2√(5).

r(2( 2√(5)) + 3( 1√(5))) = -17 r( 7√(5)) = -17 |r| = 17√(5)7
Pattern Recognition

Standard Euler line property: O, G, C are collinear and G divides OC in 2:1. Use parametric equation to find intersection distance directly without finding the intersection point.

Chapter Mix

Class 11 Maths: Straight Lines

Q23 jee_main_2024_31_jan_evening Parallelogram Properties
Let A(-2, -1), B(1, 0), C(α, β) and D(γ, δ) be the vertices of a parallelogram ABCD. If the point C lies on 2x - y = 5 and the point D lies on 3x - 2y = 6, then the value of |α + β + γ + δ| is equal to
Numerical Answer. Answer: 32 to 32

Solution

Related Formula
In a parallelogram, midpoints of diagonals coincide: ((xA+xC)/(2), (yA+yC)/(2)) = ((xB+xD)/(2), (yB+yD)/(2))
Core Logic

Parallelogram Properties diagram for Q23 - JEE Main 2024 Evening
Parallelogram Properties diagram for Q23 - JEE Main 2024 Evening

Given diagonals AC and BD bisect each other:

α - 2 = γ + 1 α - γ = 3 (1) β - 1 = δ + 0 β - δ = 1 (2)

Point C(α, β) lies on 2x - y = 5 2α - β = 5 (3) Point D(γ, δ) lies on 3x - 2y = 6 3γ - 2δ = 6 (4)

From (1) and (2), substitute γ = α - 3 and δ = β - 1 into (4):

3(α - 3) - 2(β - 1) = 6 3α - 9 - 2β + 2 = 6 3α - 2β = 13 (5)

Solve (3) and (5): From (3), β = 2α - 5. Substitute in (5):

3α - 2(2α - 5) = 13 -α + 10 = 13 α = -3

So, β = 2(-3) - 5 = -11. From earlier substitutions:

γ = -3 - 3 = -6 δ = -11 - 1 = -12

Sum of variables:

|α + β + γ + δ| = |-3 - 11 - 6 - 12| = |-32| = 32
Chapter Mix

Class 11 Maths: Straight Lines

Q10 jee_main_2024_31_jan_morning Properties of Parallelogram
Let α, β, γ, δ in Z and let A (α, β), B (1, 0), C (γ, δ) and D (1, 2) be the vertices of a parallelogram ABCD. If AB = √(10) and the points A and C lie on the line 3y = 2x + 1, then 2(α + β + γ + δ) is equal to
  • A. 10
  • B. 5
  • C. 12
  • D. 8

Solution

Core Logic

Let E be the midpoint of the diagonals AC and BD. Since ABCD is a parallelogram, the diagonals bisect each other.

Properties of Parallelogram diagram for Q10 - JEE Main 2024 Morning
Properties of Parallelogram diagram for Q10 - JEE Main 2024 Morning
Midpoint E from BD: ( (1+1)/(2), (0+2)/(2) ) = (1, 1).

Step 1: Apply Midpoint on AC

Midpoint E from AC: ( (α+γ)/(2), (β+δ)/(2) ). Equating both:

(α+γ)/(2) = 1 α + γ = 2 (β+δ)/(2) = 1 β + δ = 2
Step 2: Final Value

The expression requires 2(α + β + γ + δ).

2(2 + 2) = 2(4) = 8

(Note: Additional conditions like AB = √(10) and the line equation are extraneous data not needed to find the sum).

Chapter Mix

Class 11 Maths: Straight Lines

More Straight Lines Questions — jee_main_2026_22_january_evening

Practice all Straight Lines previous-year questions →

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