The area of the triangle formed by the lines 2x + 3y = 12, x – y – 1 = 0 and x = 0 (as shown in Fig. 3.23) , is
Given
Equation 1: 2x + 3y = 12 Equation 2: x – y = 1 Equation 3: x = 0
To calculate the Area at first we solve the Equation 1 & 2 Simultaneously by method of substitution.
We substitute the value of x from Equation 2 in Equation 1 to get the value of y
Equation 2: x – y = 1 ⇒ x = y + 1
Equation 1: 2x + 3y = 12
Substituting the value from equation 2 we get
2(y + 1) + 3y = 12 ⇒ 2y + 2 + 3y = 12 ⇒ 5y = 10 ⇒ y = 2
Putting the value in Equation 1 we get
x = 2 + 1 ⇒ x = 3
So both this lines passes through ( 3 , 2) Let this Coordinate name be P1
Equation 3 is the equation for y axis
Equation 1 meets Y axis at (0 ,4) which is calculated by substituting x = 0 in Equation 1. Let this Coordinate name be P2
Equation 2 meets Y axis at (0 , – 1) which is calculated by substituting x = 0 in Equation 2. Let this Coordinate name be P3
So Area of the triangle = *| x1 * (y2 – y3) + x2 * (y3 – y1) + x3 * (y1 – y2) |
Where x1 ,y1 are the coordinates of P1
x2, y2 are the coordinates of P2
x3 ,y3 are the coordinates of P3
⇒ Area of the Given Triangle = *| 3* (4+ 1) + 0 * ( – 1 – 2) + 0* (2– 4) |
⇒ Area of the Given Triangle = *| 3* 5 |
⇒ Area = ⇒ Area = 7.5 Sq. Units
Area of the triangle is 7.5 sq. Units