A number when multiplied by five times of itself gives the value equal to 720. What is the number?

Options

A. 13
B. 9
C. 15
D. 12

Answer

To solve the problem step by step, let's denote the unknown number as \( A \).

### Step 1: Set up the equation
The problem states that a number multiplied by five times itself equals 720. We can express this mathematically as:
\[ A \times (5A) = 720 \]

### Step 2: Simplify the equation
Now, we can simplify the left side of the equation:
\[ 5A^2 = 720 \]

### Step 3: Isolate \( A^2 \)
To isolate \( A^2 \), divide both sides of the equation by 5:
\[ A^2 = \frac{720}{5} \]
Calculating the right side gives:
\[ A^2 = 144 \]

### Step 4: Solve for \( A \)
Now, to find \( A \), we take the square root of both sides:
\[ A = \sqrt{144} \]
Calculating the square root gives:
\[ A = 12 \]

### Conclusion
Thus, the number is:
\[ \boxed{12} \]