The area of the original square patio will be 289 ft²
Step-by-step explanation
Suppose, the side length of the original square patio is
ft.
So, the area of the square patio will be:
ft²
After expanding the length by 20 ft and the width by 10 ft, the new length will be:
and the new width will be:

As the formula for area is
and the area is given as 999 ft² , so the equation will be......

Using zero-product property, we will get.....

(Negative value of x is ignores as the side length can't be in negative)
So, the area of the original square patio will be:
