The perimeter and length of a rectangle are in the ratio of 8 : 1, and the area of the rectangle is $$1323 cm^2$$. Find the length of the rectangle.
Let the length and breadth of rectangle of rectangle are $$l$$ and $$b$$ respectively
Given, Ratio of perimeter and length of the rectangle = 8 : 1
$$=$$> Â $$\frac{2\left(l+b\right)}{l}=\frac{8}{1}$$
$$=$$> Â $$\frac{l+b}{l}=\frac{4}{1}$$
$$=$$> Â $$l+b=4l$$
$$=$$> Â $$b=3l$$ ....................(1)
Area of the rectangle = $$1323 cm^2$$
$$=$$>Â Â $$lb=1323$$
$$=$$> Â $$l\left(3l\right)=1323$$
$$=$$> Â $$3l^2=1323$$
$$=$$> Â $$l^2=441$$
$$=$$> Â $$l=21$$ cm
$$\therefore\ $$Length of the rectangle = 21 cm
Hence, the correct answer is Option B
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