What approximate value should come in place of the question mark (?) in the following questions ?
Note : (You are not expected to calculate the exact value.)
`1898.88 div 189.921 + 9.99 + (?)^(2) = 83.89`

Options

A. 3
B. 4
C. 5
D. 8

Answer

To find the approximate value that should come in place of the question mark (?) in the equation:

\[ 1898.88 \div 189.921 + 9.99 + (?)^2 = 83.89 \]

we will follow these steps:

### Step 1: Approximate the values
We will round the numbers to their nearest whole numbers for simplification:
- \( 1898.88 \) is approximately \( 1899 \)
- \( 189.921 \) is approximately \( 190 \)
- \( 9.99 \) is approximately \( 10 \)
- \( 83.89 \) is approximately \( 84 \)

So, we can rewrite the equation as:

\[ 1899 \div 190 + 10 + (?)^2 = 84 \]

### Step 2: Perform the division
Now, we will perform the division:

\[ 1899 \div 190 \approx 10 \]

This gives us:

\[ 10 + 10 + (?)^2 = 84 \]

### Step 3: Combine the terms
Now, we can combine the constants:

\[ 20 + (?)^2 = 84 \]

### Step 4: Isolate the square term
To isolate the square term, we subtract \( 20 \) from both sides:

\[ (?)^2 = 84 - 20 \]

This simplifies to:

\[ (?)^2 = 64 \]

### Step 5: Solve for the question mark
Now, we take the square root of both sides to find the value of the question mark:

\[ ? = \sqrt{64} \]

This gives us:

\[ ? = 8 \]

### Final Answer
Thus, the approximate value that should come in place of the question mark (?) is \( 8 \).