Square root of 90

The square root of 90 is ±9.486.The positive value, 9.486 is the solution of the equation x² = 90. As defined, the square root is just the inverse of squaring a number, so, squaring 9.486 will result in 90.  The square root of 90 is expressed as √90 in radical form, where the ‘√’  sign is called “radical”  sign. In exponential form, it is written as (90)^1/2  .
 

We can find the square root of 90 through various methods. They are:

• Prime factorization method

• Long division method

• Approximation/Estimation method
   

The prime factorization of 90 involves breaking down a number into its factors. Divide 90 by prime numbers, and continue to divide the quotients until they can’t be separated anymore. 

• Find the prime factors of 90

• After factorizing 90, make pairs out of the factors to get the square root.

• If there exist numbers that cannot be made pairs further, we place those numbers with a “radical” sign along with the obtained pairs

So, Prime factorization of 90 = 3 × 3× 5× 2 

for 90, only one pairs of factors 3 is obtained, but a single 5 and a single 2 are remaining.

So, it can be expressed as  √90 = √(3 × 3× 5× 2) = 3√10

3√10 is the simplest radical form of √90.

This is a method used for obtaining the square root for non-perfect squares, mainly. It usually involves the division of the dividend by the divisor, getting a quotient and a remainder too sometimes.

Follow the steps to calculate the square root of 90:

Step 1 : Write the number 90, and draw a horizontal bar above the pair of digits from right to left.

Step 2 : Now, find the greatest number whose square is less than or equal to 90. Here, it is
9, Because 9²=81 < 90.

Step 3 : Now divide 90 by 9 (the number we got from Step 2) such that we get 9 as quotient and then multiply the divisor with the quotient, we get 81. Subtract 81 from 90, we get 9. Add a decimal point after the quotient 9, and bring down two zeroes and place it beside 9 to make it 900.

Step 4: Add 9 to same divisor, 9. We get 18.

Step 5: Now choose a number such that when placed at the end of 18, a 3-digit number will be formed. Multiply that particular number by the resultant number to get a number less than 900. Here, that number is 4. 
184×4=736<900.

Step 6: Do 900-736=164. Again, bring down two zeroes and make 164 as 16400. Simultaneously add the unit’s place digit of 184, i.e., 4 with 184. We get here, 188. Apply Step 5 again and again until you reach 0. 

We will show two places of precision here, and so, we are left with the remainder, 15804 (refer to the picture), after some iterations and keeping the division till here, at this point 
             
Step 7 : The quotient obtained is the square root. In this case, it is 9.486….

Estimation of square root is not the exact square root, but it is an estimate.Here, through this method, an approximate value of square root is found by guessing.

Follow the steps below:

Step 1: Find the nearest perfect square number to 90. Here, it is 81 and 100

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Step 2: We know that, √81=9 and √100=10. This implies that √90 lies between 9 and 10.

Step 3: Now we need to check √90 is closer to 9 or 9.5. Let us consider 9 and 9.5. Since (9)²=81 and (9.5)²=90.25. Thus, √90 lies between 9 and 9.5.

Step 4: Again considering precisely, we see that  √90 lies close to (9.5)²=90.25. Find squares of (9.45)²=89.302 and (9.49)²= 90.0601.

We can iterate the process and check between the squares of 9.46 and 9.48 and so on.

We observe that √90=9.486…
 

• Estimation Method:Estimation refer to a reasonable guess of the actual value to make calculations realistic and precise. This method helps in estimating the square root of a number.

• Exponential form: An algebraic expression that includes an exponent. It is a way of expressing the numbers raised to some power of their factors. It includes continuous multiplication involving base and exponent.Ex: 3× 3 × 3 × 3 = 81 or, 3 ⁴ = 81, where 3 is the base, 4 is the exponent 

• Prime Factorization:  Expressing the given expression as a product of its factors Ex: 52=2 × 2 × 13 

•  Prime Numbers: Numbers which are greater than 1, having only 2 factors as →1 and Itself. Ex: 1,3,5,7,....

•  Rational numbers and Irrational numbers: The Number which can be expressed as p/q, where p and q are integers and q not equal to 0 are called Rational numbers. Numbers which cannot be expressed as p/q, where p and q are integers and q not equal to 0 are called Irrational numbers. 

•  Perfect and non-perfect square numbers: Perfect square numbers are those numbers whose square roots do not include decimal places. Ex: 4,9,25 Non-perfect square numbers are those numbers whose square roots comprise decimal places. Ex :2, 8, 18