Which is the area of a rectangle with a length of 21 feet and a width of 15 feet

Step-by-step explanation:

In order to calculate the area of a rectangle, you can use the following formula:

Where "l" is the lenght of the rectangle and "w" is the width.

In this case you know that this rectangle has a length of 21 feet and a width of 15 feet. Then:

Therefore, you can substitute these values into the formula, getting that the area of this rectangle is:

$20.01

step-by-step explanation:

the sale price is (1.00 - 0.77)($87), or 0.23($87), or $20.01.

step-by-step explanation:

if you want to solve percent error follow these steps.

1. subtract the accepted value from the experimental value.

2. take the absolute value of step 1.

3. divide that answer by the accepted value.

4. multiply that answer by 100 and add the % symbol to express the answer as a percentage.

if you want to solve percent of change just do this.

1. work out the difference (increase) between the two numbers you are comparing.

2. divide the increase by the original number and multiply the answer by 100. if your answer is a negative number then this is a percentage decrease.

hope this : )