Find the value of question mark(?) in the following questions ?
64% of 750 + `(?)^2` = 649

Options

A. 14
B. 12
C. 11
D. 13

Answer

To find the value of the question mark (?) in the equation \( 64\% \text{ of } 750 + (?)^2 = 649 \), we can follow these steps:

### Step 1: Calculate 64% of 750
To find 64% of 750, we can convert the percentage to a fraction and multiply:
\[ 64\% = \frac{64}{100} = 0.64 \]
Now, calculate:
\[ 0.64 \times 750 \]

### Step 2: Perform the multiplication
Calculating \( 0.64 \times 750 \):
\[ 0.64 \times 750 = 480 \]

### Step 3: Substitute back into the equation
Now substitute this value back into the original equation:
\[ 480 + (?)^2 = 649 \]

### Step 4: Isolate the square term
To isolate \( (?)^2 \), subtract 480 from both sides:
\[ (?)^2 = 649 - 480 \]

### Step 5: Perform the subtraction
Calculating \( 649 - 480 \):
\[ 649 - 480 = 169 \]

### Step 6: Take the square root
Now, we take the square root of both sides to find the value of ?:
\[ ? = \sqrt{169} \]

### Step 7: Calculate the square root
The square root of 169 is:
\[ ? = 13 \]

Thus, the value of the question mark (?) is **13**.

---