The answer is 6⁴.
Exponent is the number of times the factor is being multiplied. For example:
x * x = x²
x * x * x = x³
x * x * x * x = x⁴
....
So: 
6 * 6 * 6 *6 = 6⁴
        
             
        
        
        
Obtuse angle 
Operation
Order of operation
        
                    
             
        
        
        
In order to write in scientific notation you have to write an expression with a whole number times 10 to a certain exponent. In this case the nearest whole number would be 7.65 and you have to move the decimal place twice to the left to get the desired number. Thus, the exponent would be a negative number. The final answer is : 7.65 x 10^-2.