Answer:
Hey There!
Let's solve...
Here it is a rectangular floor with length =21 cm and width =15cm
So

So now We need to convert it to yards square

So how this 9 ft^2 came??
Let's know

<h2>I hope it is helpful to you...</h2><h3>Cheers!_______</h3>
1/8 of all=mystery
mystery=3
'of' means multiply
therefor
1/8 times all=3
multiply both sides by 8/1 to clear fracion
all=24
Each Had 10. Y= 4. Because 3 x 4 = 12 + 8 = 20 ÷ 2 = 10