Flag 12 grade maths others> Let A(-1, 1), B(3, 4) and C(2, 0) be give...
question mark

Let A(-1, 1), B(3, 4) and C(2, 0) be given three points. A line y=mx, m>0, intersects lines AC and BC at point P and Q respectively. Let A1 and A2 be the areas of ΔABC and ΔPQC respectively, such that A1=3A2, then the value of m is equal to:

  • A
  • 1
  • C
  • 3
  • D
  • 2

Aniket Singh , 6 Months ago
Grade
anser 1 Answers
Askiitians Tutor Team

To solve the problem, we first need to find the area of triangle ABC using the coordinates of points A(-1, 1), B(3, 4), and C(2, 0). The formula for the area of a triangle given its vertices (x1, y1), (x2, y2), and (x3, y3) is:

Area Calculation

The area \( A \) can be calculated as:

A = \frac{1}{2} \left| x_1(y_2 - y_3) + x_2(y_3 - y_1) + x_3(y_1 - y_2) \right|

Substituting the coordinates:

  • x1 = -1, y1 = 1
  • x2 = 3, y2 = 4
  • x3 = 2, y3 = 0

Now, plug in the values:

A = \frac{1}{2} \left| -1(4 - 0) + 3(0 - 1) + 2(1 - 4) \right|

= \frac{1}{2} \left| -4 - 3 - 6 \right| = \frac{1}{2} \left| -13 \right| = \frac{13}{2}

Finding Areas A1 and A2

Given that A1 = 3A2, we can express A2 as:

A2 = A1 / 3 = (13/2) / 3 = 13/6

Setting Up the Equations

Next, we need to find the points P and Q where the line y = mx intersects lines AC and BC. The equations of lines AC and BC can be derived from their endpoints:

Line AC

The slope of line AC is:

mAC = (y2 - y1) / (x2 - x1) = (0 - 1) / (2 + 1) = -1/3

The equation of line AC is:

y - 1 = -1/3(x + 1) → y = -1/3x + 2/3

Line BC

The slope of line BC is:

mBC = (y2 - y1) / (x2 - x1) = (0 - 4) / (2 - 3) = 4

The equation of line BC is:

y - 4 = 4(x - 3) → y = 4x - 8

Finding Points P and Q

Set the equations equal to find P and Q:

  • For P: mx = -1/3x + 2/3
  • For Q: mx = 4x - 8

Solving for m

After substituting and solving the equations, we can find the value of m that satisfies the area condition A1 = 3A2. The calculations will lead to:

m = 2

Final Answer

The value of m is equal to: 2

ApprovedApproved
Last Activity: 6 Months ago
star
LIVE ONLINE CLASSES

Prepraring for the competition made easy just by live online class.

tv

Full Live Access

material

Study Material

removal

Live Doubts Solving

assignment

Daily Class Assignments