The error is that he probably forgot the decimal point thus causing him to say '"hundred" instead of "and" for the decimal point.
        
             
        
        
        
360 ÷ 12 = 30.
The measure of an interior angle of a dodecagon is 30°. (:
        
             
        
        
        
Answer:
5-√9/4    4-3√-16    3+2√-9➗7
Step-by-step explanation: