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The area of the region bounded by the lines x+2y=12,x=2,x=6x+2 y=12, x=2, x=6 and xx-axis is :

Solution

✅ Correct Option: 4

Identifying the region by finding the intersection points:

  • The xx-axis corresponds to y=0y=0
    • When y=0y=0 in x+2y=12x+2y=12, we get x=12x=12
    • Our region is bounded by x=2x=2 and x=6x=6, which are vertical lines

Expressing yy in terms of xx for the sloped boundary:

From x+2y=12x+2y=12, I can solve for yy:

2y=12−x2y = 12-x

y=12−x2=6−x2y = \dfrac{12-x}{2} = 6-\dfrac{x}{2}


Finding intersection points to define the region completely:

At x=2x=2: y=6−22=5y = 6-\dfrac{2}{2} = 5

At x=6x=6: y=6−62=3y = 6-\dfrac{6}{2} = 3


Calculating the area using integration:

Area=∫26(6−x2) dx\text{Area} = \int_{2}^{6} (6-\dfrac{x}{2}) \, dx

Area=[6x−x24]26\text{Area} = [6x - \dfrac{x^2}{4}]_{2}^{6}

Area=(6(6)−624)−(6(2)−224)\text{Area} = \left(6(6) - \dfrac{6^2}{4}\right) - \left(6(2) - \dfrac{2^2}{4}\right)

Area=(36−364)−(12−44)\text{Area} = \left(36 - \dfrac{36}{4}\right) - \left(12 - \dfrac{4}{4}\right)

Area=(36−9)−(12−1)\text{Area} = \left(36 - 9\right) - \left(12 - 1\right)

Area=27−11=16\text{Area} = 27 - 11 = 16


Alternatively, using the trapezoid formula:

Area=12×width×(height1+height2)=12×4×(5+3)=16\text{Area} = \dfrac{1}{2} \times \text{width} \times (\text{height}_1 + \text{height}_2) = \dfrac{1}{2} \times 4 \times (5 + 3) = 16

Therefore, the area of the region is 16 square units.

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