Hello, students, today we are going begin new chapter that is Cube and cube roots, a very lovely chapter. Let’s proceed ahead students and study about cube and cube roots.
So, students we have to now find out the cube of 2. In order to find cube of a number just multiply the number 3 times. So the number over here is 2 and to find the cube of 2 just multiply the number 3 times. So, what are we going to do over here, we will multiply the number 3 times, 2 multiplied by 2 multiplied by 2, which is equal to 8. Now, students, this can also be written in index form as 2 raise to 3. So, students 2 raise to 3 is equal to 8.
Proceeding ahead students, how to find the cube of a number? We just found the cube of the number. But we will now go step by step. So, find the cube of 3 that is 3 raise to 3. So, first step will be to find the cube of 3, multiply 3 three times. So, what will happen over here, 3 multiplied by 3 multiplied by 3. Now, students 3 multiplied 3 will be equal to 9, 9 will be again multiplied by 3. So, 9 multiplied by 3 will be equal to 27. Students, cube of 3 is written as 3 raise to 3 is equal to 27 or this means cube of 3 is equal to 27.
Moving ahead, students, with exercise number 45. The first question says, evaluate the following and write which number is the cube of which other number. So, the first number given to us is 3 and we have to find out the cube of 3. So, solution, 3 raise to 3, we will have to multiply 3 three times. So, students this will be written as 3 into 3 into 3, 3 multiplied by 3 is equal to 9, 9 multiplied 3 is equal to 27. So, students, 27 is the cube of 3.
Moving ahead with the next question, where we have to find the cube of 7. So, this is written as 7 raise to 3. We will have to multiple 7 three times. So, students this will be written as 7 multiplied 7 multiplied by 7. 7 multiplied 7 is equal to 49, 49 multiplied by 7 is equal to 343. So, students, 343 is the cube of 7.