do now 1 (5 min) 1.define a square root. 2.what is the square root of 81? 3.what is five squared?...
TRANSCRIPT
Do Now 1 (5 min)1. Define a square root.2. What is the square root of 81?3. What is five squared?4. What is the difference between
perfect and imperfect squares?
REMEMBER! Do not turn in your HW this morning. We will be going over the worksheet and using it for HW tonight!
Cubes• To cube a number, you multiply it by
itself three times.• Example: 3 Cubed (33) =3 × 3 × 3 =
27
Perfect Cubes
Perfect Cube = a whole number that is formed by multiplying one whole number by itself three times.
Example:27 is a perfect cube because…
3 x 3 x 3 = 27
Perfect Cubes/Roots• The cube root of 27 = 3
273
27
3
Cube
Cube Root3 x 3 x 3 = 27
Perfect Cubes/Roots• The cube root of 64 = 4
643
64
4
Cube
Cube Root4 x 4 x 4 = 64
Perfect Cubes/RootsRoot 1 2 3 4 5 6Perfect Cube
1 8 27 64125
216
Memorize or not?
Root 7 8 9 10Perfect Cube
343512
7291,000
You will have a copy of this for estimation!!
STOP AND JOT 1
1.) How else can we write 5 x 5 x 5?2.) How else can we write “the cube root of
216”?3.) What is a perfect cube?4.) What is a perfect cube root?
Imperfect Cubes/Roots
Imperfect Cube = a whole number that is formed by multiplying one non-whole number by itself three times.
Example:40 is an imperfect cube because…
3.4 x 3.4 x 3.4 = 40
Imperfect Cubes/Roots• The cube root of 40 = 3.4
403
40
3.4
Cube
Cube Root3.4 x 3.4 x 3.4 = 40
Example: Estimating Imperfect Cube Roots
Root 1 2 3 4 5 6Perfect Cube
1 8 27 64125
216
Steps:
1)Refer to perfect cubes close to the number you are estimating.
2)Make an estimation using the number line.
Example: Estimating Imperfect Cube Roots
Root 1 2 3 4 5 6Perfect Cube
1 8 27 64125
216
--Problem: --We look between 64 and 27. - -Since 40 is about in the middle of 27 and 64, we
are looking for a root roughly in the middle of 3 and 4.
403
Stop and Jot 2
• Use the chart to estimate
703
Root 1 2 3 4 5 6Perfect Cube
1 8 27 64125
216
“Show what you know!”
• Use the chart to estimate
703Root 1 2 3 4 5 6Perfect Cube
1 8 27 64125
216
2163
2003
173
A.)
B.)
C.)
1.) 5 2.) 4 3.) 5.5 4) 6
1.) 5 2.) 6 3) 5.8 4.) 4.9
1.) 2.1 2.) 2.9 3.) 3.0 4) 2.6
EXIT TICKET
1.) What is a cube root?2.) What is the difference between a perfect
cube and an imperfect cube?3.) 4.)5.)
Root 1 2 3 4 5 6Perfect Cube
1 8 27 64125
216
273
803
2053
• Use the chart to estimate
703
4003
8003
5003
4.)
5.)
6.)
Root 7 8 9 10Perfect Cube
343512
729
1,000