Slide 1 : By: Tracy Balow & Kristen Moorhouse
Slide 2 : Which is the better buy? 12 inch
thin crust pizza
for
$10.99 9 inch
thin crust pizza
for
$7.99
Slide 3 : To solve this problem, which concept will you need to use? a) the circumference of a circle b) the area of a circle OR Think, pair, share…
Slide 4 : You would use circumference if you only wanted to eat the crust. Click on the pizza to continue.
Slide 5 : You would use area to find out how much pizza there is!
Slide 6 : Now… can you write the formula to find the area of a circle? A = πr2 Think, pair, share…
Now, find the area of each pizza.Round to the nearest hundredth. : Now, find the area of each pizza.Round to the nearest hundredth. 12” pizza
A = πr2
A = 3.14(6)2
A = 3.14(36)
A = 113.04 in2 9” pizza
A = πr2
A = 3.14(4.5)2
A = 3.14(20.25)
A = 63.59 in2 Remember the radius is half the diameter! Think, pair, share…
Now, how can we use that information to find the better buy? : Now, how can we use that information to find the better buy? Recall, to find the better buy, you need to find the price per one unit (the unit rate!).
Soooooo, take the price and divide it by the area of the pizza.
This will give you the price per square inch of pizza!
Do this for both pizzas so you can compare their unit prices. Vs. Think, pair, share…
Now, find the unit rate of each pizza.Round to the nearest hundredth. : Now, find the unit rate of each pizza.Round to the nearest hundredth. 12” pizza
$10.99
113.04 in2
= 0.0972
= $0.10/in2 9” pizza
$7.99
63.59 in2
= 0.1256
= $0.13/in2 Vs. Think, pair, share…
So, after doing all that work and getting all those answers… : So, after doing all that work and getting all those answers… And…. Think, pair, share…
Let’s review…. : Let’s review…. What did the original question ask?
What vocabulary did we need to know?
What information did we need to know to solve the problem? How did we solve the problem? What were the steps?
How can we check our answer?
What standards were addressed?
Finally…. : Finally…. Think, pair, share…