Presentation on theme: "Direct Proportion Honors Math – Grade 6. Problem of the Day Tracy works at home reading and correcting manuscript for a small local newsletter publisher."— Presentation transcript:
Problem of the Day Tracy works at home reading and correcting manuscript for a small local newsletter publisher. If she works for 5 hours, she earns $70. At that rate, how many hours must she work to earn $630? KEY CONCEPT Direct Proportion Two quantities have a direct poroportion relationship when an increase or decrease in one quantity causes the same kind of change in the other quantity. The amount Tracy earns depends directly on the number of hours she works. To find the number of hours, write and solve a direct proportion. What are the important facts?
When solving a problem involving a direct proportion, there are two ways to setup the proportion. Method 1: Use Unlike UnitsMethod 2: Use Like Units Tracy must work 45 hours to earn $630.
A mass hanging on a spring causes the spring to stretch. The length of the spring when stretched is in direct proportion to the force applied by the mass. If a 3-kilogram mass stretches a spring so that it is 63 cm long, what will be the length of the spring if the force of a 5-kg mass is used? Method 1: Use Unlike UnitsMethod 2: Use Like Units
A sample of paint contains 3 ounces of blue paint and 8 ounces of yellow point. If you have a 24-ounce can of the blue paint, how much yellow paint show you mix with it in order to make the same color as the sample? Method 1: Use Unlike UnitsMethod 2: Use Like Units
At what average speed can a locust fly if it can travel 46 meters in 5 seconds? Method 1: Use Unlike UnitsMethod 2: Use Like Units Average speed is represented as a unit rate. Units to 1 measure of time.
A direct proportion can be represented by a graph. Write equivalent ratios. Write the ratios as coordinates.Notice the graph of a direct proportion is a straight line slanting upward from left to right. The number of pages Mike reads and the numbers of hours are in direct proportion.