Question

The breadth and length of a rectangle are in the ratio 4:5 and its are is 320 squares metres what are the length and breadth

Answer 1

ANSWER WITH FULL EXPLANATION

Area of the rectangle = 320 $m^{2}$

Ratio of the breadth of the rectangle to length = 4:5
Let the breadth be $4x$ m and the length be $5x$ m. 

Now, 
Length × Breadth = Area
⇒ $5x*4x=320$
⇒ $5*x*4*x=320$
⇒ $5*4*x*x=320$
⇒ $20x^{2}=320$
⇒ $\frac{20x^{2}}{20}=\frac{320}{20}$    [Dividing both sides by 20. ]
⇒ $x^{2}=16$
⇒ $\sqrt{x^{2}}=\sqrt{16}$    [Square root both sides. ]
⇒ $x=4$

∴ Length of the rectangle = $5x$ m = (5 × 4) m = 20 m
   Breadth of the rectangle = $4x$ m = (4 × 4) m = 16 m

Congrats ! We have found the answer. 

Hope this may help you. 

If you have any doubt, then you can ask me in the comments.