RO divides the rectangle into two congruent right triangles.
The area of the one triangle is equal half area of the rectangle.
Calculate the area of rectangle:

The area of right triangle:

Use the Pythagorean theorem to calculate the length of RO:

The formula of an area of this right triangle is:

Therefore we have the equation:

If there were 49 cars in a line that stretched 528 feet, what is the average car length? assume that the cars are lined up bumper-to-bumper
Answer: We are given there are 49 cars
Also these 49 cars are in a line stretched 528 feet.
Now the average length of the car is:
Average length = 
=
Therefore, the average length of car is 10.78 feet
Let's solve the first inequality at first. So,
−2(x + 4) + 10 < x − 7
-2x- 8 + 10 < x - 7 By distribution property.
-2x + 2 < x - 7 Adding the like terms.
-2x < x - 7 - 2 Subtract 2 from each sides.
-2x < x - 9 By simplifying.
-2x - x < -9 Subtract x from each sides.
-3x < -9
Since we are dividing by negative 3. So, sign of inequality will get change.
So, x>3
Now the next inequality is,
−2x + 9 > 3(x + 8)
-2x + 9 > 3x + 24
-2x > 3x + 24 - 9
-2x > 3x + 15
-2x - 3x > 15
-5x >15

So, x <-3
Hence, the correct choice is x > 3 or x < −3.