Answer:
She is going at the rate of 4.5 feet per second.
Step-by-step explanation:
Given:
The rate of walking is 90 yards per minute.
Now, to find the rate in feet per second.
1 yard = 3 foot.
1 minute = 60 seconds.
So, first we find the rate of walking per second in yard = 
Therefore by dividing we get =
Now, we find the rate of walking per second in feet = 
So, by multiplying we get = 
Therefore, she is going at the rate of 4.5 feet per second.
In order to determine the value of x, consider that one of the interior angles of the triangle is given by:
180 - (4x - 18)
= 180 - 4x + 18
= 198 - 4x
Next, consider that the sum of the interioir angles of a triangle is equal to 180:
(2x + 6) + 36 + (198 - 4x)
= 2x + 6 + 36 + 198 - 4x
= -2x + 240
this is equal to 180:
-2x + 240 = 180
-2x = 180 - 240
-2x = -60
x = 60/2
x = 30
Hence, the value of x is x = 30