Do Now 1 (5 min) Define a square root. What is the square root of 81? REMEMBER! Do not turn in your HW this morning. We will be going over the worksheet and using it for HW tonight! Do Now 1 (5 min) Define a square root. What is the square root of 81? What is five squared? What is the difference between perfect and imperfect squares? Objective:I can define cube roots and find both perfect and imperfect examples.

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 Cube 27 3 Cube Root 3 x 3 x 3 = 27 The cube root of 27 = 3 Cube 27 3 Cube Root 3 x 3 x 3 = 27

Perfect Cubes/Roots Cube 64 4 Cube Root 4 x 4 x 4 = 64 The cube root of 64 = 4 Cube 64 4 Cube Root 4 x 4 x 4 = 64

Perfect Cubes/Roots Root 1 2 3 4 5 6 8 27 64 125 216 Root 7 8 9 10 343 512 729 1,000 Memorize or not? 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 Cube 40 3.4 Cube Root 3.4 x 3.4 x 3.4 = 40

Example: Estimating Imperfect Cube Roots 1 2 3 4 5 6 Perfect Cube 8 27 64 125 216 Steps: Refer to perfect cubes close to the number you are estimating. Make an estimation using the number line.

Example: Estimating Imperfect Cube Roots 1 2 3 4 5 6 Perfect Cube 8 27 64 125 216 --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.

Stop and Jot 2 Use the chart to estimate Root 1 2 3 4 5 6 Perfect Cube 8 27 64 125 216

“Show what you know!” Root 1 2 3 4 5 6 8 27 64 125 216 Perfect Cube 8 27 64 125 216 Use the chart to estimate 1.) 5 2.) 4 3.) 5.5 4) 6 A.) B.) 1.) 5 2.) 6 3) 5.8 4.) 4.9 C.) 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 6 Perfect Cube 8 27 64 125 216

Root 7 8 9 10 343 512 729 1,000 Use the chart to estimate Perfect Cube 4.) 5.) 6.)