C C S S . 6 . R P. 3 : U S I N G P R O P O R T I O N A L R E A S O N I N G T O S O LV E R E A L - W O R L D P R O B L E M S .

GEORGE WASHINGTON’S NOSE

Be ready to learn! You need your Journal, a pencil, calculator and a ruler.

WHAT’S A PROPORTION?COPY THESE NOTES INTO YOUR JOURNAL!

• A proportion is an equation you write to show that 2 ratios are equal.• The equation = is a proportion. We say, “The

ratio 2 cm to 3 ft. is equal to the ratio 8 cm to 12 ft.”• Find the missing part of the proportion:

3 green Skittles : 4 red Skittles = 6 green Skittles : ? Red SkittlesApplication: On the map we see a scale that is 1 inch : 48 miles. How far is it from Boise to Omaha, Nebraska?Today you will use proportions to solve a problem. Pay attention to labels!!!

Casey was on summer vacation and visited Mt. Rushmore in S. Dakota. The park ranger gave a talk that described the history of the monument and provided some interesting facts. Casey could not believe that the carving of George Washington’s face is 60 feet tall from his chin to the top of his head!

HOWEVER , WHEN A TOURIST ASKED ABOUT THE LENGTH OF WASHINGTON’S NOSE, THE RANGER WAS

STUMPED!

MT. RUSHMORE

CASEY CAME TO HER RESCUE BY MEASURING, CALCULAT ING AND GET T ING AN ANSWER . HOW D ID

CASEY GET HER ANSWER?

MT. RUSHMORE

Remember the park ranger said the carving of George Washington’s face is 60 feet tall from his chin to the top of his head!

YOUR TASK: Figure out the length in feet of George Washington’s nose on the monument. Work with your educational partners to come up with a strategy. Show all measurements and calculations in your Math journals with clear labels so that anyone could understand your work. Measure the resources in cm.

RESOURCES:

• There will be 6 different resources used for this task:1. Dollar bills2. Picture of Mt. Rushmore3. Sketch of George Washington4. Bust of George Washington5. Human faces6. Picture on Library of Congress papers

We will compare calculations in 15 minutes.

COMPARE RESULTS!

• You set up a proportion. = • You measured the distance from chin to the top of

his head in cm.• You measured the length of his nose on the

resource you were given in cm. • You found the proportion in feet.• How close were our measurements using the

different resources?

SOLVE THE PROPORTIONS IN YOUR JOURNALS.

1. =

2. =

3. =

4. =