Rectilinear area lesson
Presentation
•
Mathematics
•
3rd Grade
•
Easy
Standards-aligned
Jeane Lakin
Used 19+ times
FREE Resource
10 Slides • 6 Questions
1
Target
I can take my area model chopping to the next level.
2
Poll
Which type of area model is this?
3
Multiple Choice
Which equation best matches the area model?
4
L = length (how long)
W = width (how wide)
L goes first in L x W. If you switch it around, the total area is the same, BUT the area model would rotate (remember that commutative property?).
5
Enough warm up. Are you ready to turn up our math a little?
We are going step by step. Stay together. Try not to blink. 😜
6
Multiple Choice
What is the total area of this rectangle? It has a length of 12 units and a width of 10 units. You can use your multiplication chart to help you.
7
Multiple Choice
What is the total area of this rectilinear shape?
8
Multiple Choice
But.... what happens when a side is too big for us to solve easily?
9
We CHOP it up into not 1..2...3 small rectangles!
We have 3 rectangles now
A, B, and C
Which small rectangle can we solve right away?
We have to do some work on the next slide to figure out the other sides.
10
Hmm... what can we do?
We already know rectangle C is 5 x 6 because...
But we need to figure out....
11
Fancy, fun, easy trick with rectangles!
What did you notice?
Why does it work?
12
Next up: rectangle A
We already know the width is 8.
How can we find the length of rectangle A? It is not 25.. that is the length of A + B.
13
Let's start putting this together!
A = 10 x 8 = ?
B = 5 x 8 = ?
C = 5 x 6 = ?
If you are zooming, don't say the total area yet! Wait for a few more slides...
14
Almost there...!
80 + 40 + 30 = (don't say it yet, wait for the next slide)
15
Multiple Choice
The total area of this shape is...
16
Yay!
Now if we have time... try this out in seesaw!
Target
I can take my area model chopping to the next level.
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