5.5+Application+Problems+with+Decimals

Section 5.5 - Application Problems with Decimals
Decimals are everywhere in real world situations!


 * Earnings**

If only my boss would pay me a nice, even $100 an hour and I worked exactly five hours per day -- it would be very easy to calculate my pay by multiplying those two numbers. But $9.34 is the real world pay and I work 25.34 hours a week. So, with decimal numbers, do it the same way - it just takes a minute longer.


 * Area of a Rectangle**

We have covered area of a rectangle elsewhere. Area = length x width. But what if decimal numbers are involved? Same rules.


 * Circumference**

Circumference = the distance around a circle. In order to figure out the circumference, you need to know either the diameter of the circle, or the radius, and you need to remember that pi = about 3.14. C=2(pi)(r)


 * Area of a Circle**

Confusingly similar to circumference, the area of a circle is A=(pi)(r)(r)


 * Gas Mileage**

You went exactly 400 miles on exactly 10 gallons of gas? Not in real life you didn't. More like 314 miles on 12.45 gallons of gas. Requires division by decimal numbers.


 * Shopping**

Let's see, six sweaters at $24.37 each would be?


 * d=rt**

Distance = rate x time. d=rt

If you drove 30.4 miles at a speed of 12.6 miles per hour, how long would it take to get there?


 * Solving for X**

No difference in the rules for solving for X with decimals!

Simplify both sides by using the Distributive Property and/or combining like terms. Isolate the variable from the constants by adding or subtracting the same thing from both sides. Divide both sides by the decimal coefficient.


 * Chapter Five Practice Problems**

**Where to from here?**
5.1 Decimals and Fractions 5.2 Adding and Subtracting Decimals 5.3 Multiplying Decimals 5.4 Dividing Decimals 5.5 Application Problems with Decimals Chapter Five Summary Chapter Five Homework