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The area of the smaller region bounded by the ellipse x216+y29=1\frac{x^2}{16} + \frac{y^2}{9} = 1 and the straight line 3x+4y=123x + 4y = 12 is:

Solution

✅ Correct Option: 4

The ellipse is x216+y29=1\frac{x^2}{16} + \frac{y^2}{9} = 1 with a2=16a^2 = 16 and b2=9b^2 = 9, giving a=4a = 4 and b=3b = 3.

The ellipse intersects the x-axis at (±4,0)(\pm 4, 0) and the y-axis at (0,±3)(0, \pm 3).


The line 3x+4y=123x + 4y = 12 can be rewritten in intercept form by dividing by 12:

x4+y3=1\frac{x}{4} + \frac{y}{3} = 1

The line crosses the x-axis at (4,0)(4, 0) and the y-axis at (0,3)(0, 3).


For point (4,0)(4, 0):

4216+029=1616+0=1\frac{4^2}{16} + \frac{0^2}{9} = \frac{16}{16} + 0 = 1

For point (0,3)(0, 3):

0216+329=0+99=1\frac{0^2}{16} + \frac{3^2}{9} = 0 + \frac{9}{9} = 1

Both points lie on the ellipse, so the line connects two points on the ellipse in the first quadrant.


The line divides the first quadrant portion of the ellipse into two regions: a curved region between the ellipse and the line (smaller region), and a triangular region between the line and the axes.

The smaller region area equals the quarter ellipse area minus the triangle area.


Total ellipse area =πab= \pi ab

=π×4×3= \pi \times 4 \times 3

=12π= 12\pi

Quarter ellipse area =12π4= \frac{12\pi}{4}

=3π= 3\pi sq units


The triangle has vertices at (0,0)(0, 0), (4,0)(4, 0), and (0,3)(0, 3).

Triangle area =12×base×height= \frac{1}{2} \times \text{base} \times \text{height}

=12×4×3= \frac{1}{2} \times 4 \times 3

=6= 6 sq units


Smaller region area =3π−6= 3\pi - 6 sq units

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