Answer: 
Step-by-step explanation:
<h3>
The complete exercise is: "A rectangular yard is 20 ft by 15 ft. The yard is cover with grass except for 8.5 feet square flower garden. How much grass is in the yard?"</h3><h3 />
The area of a rectangle can be calculated with the following formula:

Where "l" is the lenght of the rectangle and "w" is the width.
Based on the data given in the exercise, you can identify tha the length and the width of the rectangular yard are:

Then, you can substitute these values into the formula and then evaluate in order to find the area of the entire yard:

The area of the flower garden which is an square, can be calculated with this formula:

Where "s" is the side length.
In this case you know that:

Then the area of the flower garden is:

<em> </em>Since this is not covered with grass, you need to subtract both areas calculated above in order to find the surface covered with grass in the yard.
This is:

Answer:
Permutation
504 ways
Step-by-step explanation:
The difference between combinations and permutations is ordering. With permutations we DO care about the order of the elements, whereas with combinations we don't.
In your graphing calculator, type
nPr(9,3)
(9 letters in trapezoid, 3 letter combos)
and it returns 504.
Answer: $ 67.03
Step-by-step explanation:
Given : The average expenditure in a sample survey of 50 male consumers was $135.67, and the average expenditure in a sample survey of 38 female consumers was $68.64.
i.e. 
The best point estimate of the difference between the two population means is given by :-

Hence, the point estimate of the difference between the population mean expenditure for males and the population mean expenditure for females : $ 67.03
Answer:
acute: ZXB
right: WBZ, XBY, XBZ, ZBW
obtuse: YXZ,
straight: WBX, YBZ, ZBY,
not:
Step-by-step explanation: