solving proportions math connections ii fall 2012 ms. catalan
TRANSCRIPT
Solving Proportions
Math Connections IIFall 2012
Ms. Catalan
Objectives
Students will be able to:
(1) DESCRIBE a proportional relationship using an equation
(2) SOLVE proportions
(3) USE proportions to solve real-world problems
Definition
Example:In a recipe for chocolate chip cookies, there are TWO cups of flour for every ONEcup of sugar
Ratio:1
2
RATIO a comparison
of two quantities by
division
Definition
Example:In the recipe for chocolate chip cookies, there are TWO cups of flour for every ONE cup of sugar
If you double the recipe, then you will need FOUR cups of flour and TWO cups of sugar.
Proportion:2
4
1
2
PROPORTION
An equation stating that
two ratios are equal
Write Your Own Proportion
The wait time for a roller coaster is 20 minutes when
there are 160 people in line. At this rate, how long is the wait time when 220 people
are in line?
220160
20 xANSWER:
x = number of minutes of wait time when there are 220
people in line
Let’s Solve…
1.Cross Multiply
220160
20 x
220160
20 x
160 x = 20 (220)
Let’s Solve…
2. Solve for x.
160 x = 20 (220)
160 x = 4400 160 160
160 x = 4400
x = 27.5 minutes
But How Tall Is It??
The Washington Monument in
Washington, DC was completed in 1884.
It is the world's tallest stone
structure and the world's tallest
obelisk.(click here for definition)
In this picture, the monument is 5 inches
tall and the flags surrounding it are 0.05 inches tall.
The flags are 70 inches tall is real
life.
Write a proportion and solve to find
how tall the Washington
Monument is.
But How Tall
Is It??
5 in.
0.05 in.
x
70
5
05.0
But How Tall Is It??
x = height of monument
350 = 0.05 x
7,000 in. = xThe monument is
approximately 7,000 inches tall!
Click here for 10 amazing facts
about the Washington Monument.
Solve for the heights of these monuments.
The Jefferson Memorial
The Martin Luther King Jr. Memorial
7.5 in.
2 in.
(the man is 62 inches tall in real-life)
(the tour guide is 72 inches tall in real-life)
1 in.
5 in.
The Jefferson Memorial, built in
1947, stands approximately 230
inches tall!
The MLK Jr. Memorial is the
newest memorial in Washington, DC, opening is August 2011, and stands
approximately 360 inches tall!
How Did You Do?
Homework
Click link for Ticket to Leave
Access homework at Ms. Catalan’s
homepage
References
Carter, J. A., Cuevas, A. J., Day, R., & Malloy, C. (2012). Pre-algebra. New York, NY: Mc-Graw Hill Education.
Indiana Honey. (Photographer) (2009). Honey chocolate chip cookies [Web]. Retrieved from http://www.indianahoney.com/ihf/cookies/cookies.html
LaaLoosh. (Photographer) (n.d.). Chocolate chip cookies recipe – 1 point value [Web]. Retrieved from http://www.laaloosh.com/2009/02/11/weight-watchers-chocolate-chip-cookies-recipe/
My Teenage Werewolf. (Photographer) (n.d.). The wide ride >> roller coaster [Web]. Retrieved from http://www.myteenagewerewolf.com/lauren/the-wild-ride/attachment/roller-coaster/
Washington Monument – 10 Amazing Facts. (n.d.). YouTube. Retrieved June 24, 2012, from http://www.youtube.com/watch?v=Rs25V7VsrWY