advertisement

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) 1. 2. 3. 4. Define a square root. What is the square root of 81? What is five squared? What is the difference between perfect and imperfect squares? • 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 • The cube root of 27 Cube 3 27 = 3 27 3 3 x 3 x 3 = 27 Cube Root • The cube root of 64 Cube 3 64 = 4 64 4 4 x 4 x 4 = 64 Cube Root Root Perfect Cube 1 2 1 8 3 27 4 64 5 6 125 216 Root 7 Perfect MemorizeCube or not? 343 512 729 1,000 8 You will have a copy of this for estimation!! 9 10 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 • The cube root of 40 Cube 3 40= 3.4 40 3.4 3.4 x 3.4 x 3.4 = 40 Cube Root Root Perfect Cube 1 2 1 8 3 27 4 64 5 6 125 216 Steps: 1)Refer to perfect cubes close to the number you are estimating. 2)Make an estimation using the number line. Root Perfect Cube 1 2 1 8 3 27 4 64 5 6 125 216 --Problem: 3 40 --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 Perfect Cube 1 2 1 8 3 3 27 70 4 64 5 6 125 216 “Show what you know!” Root 2 3 3 704 • Use the chart 1 to estimate Perfect Cube 1 8 27 64 A.) 3 216 B.) 3 200 C.) 3 17 1.) 5 1.) 5 1.) 2.1 2.) 4 2.) 6 2.) 2.9 3.) 5.5 3) 5.8 3.) 3.0 4) 6 4.) 4.9 4) 2.6 5 6 125 216 EXIT TICKET 1.) What is a cube root? 2.) What is the difference between a perfect cube and an imperfect cube? 3.) 3 27 4.) 3 80 5.) 3 205 Root Perfect Cube 1 2 1 8 3 27 4 64 5 6 125 216 7 estimate 8 •Root Use the chart to Perfect Cube 4.) 3 400 5.) 3 800 6.) 3 500 970 10 51 1,00 343 729 2 0 3