Find the value of the lettered angles in each of the following ( see image ). Please show workings.

The only given Angles are 40° , 60° , 10°​

The graph shows the decibel measure for sounds depending on how many times as intense they are as the threshold of sound. noise in a quiet room is 500 times as intense as the threshold of sound. what is the decibel measurement for the quiet room? 20 decibels28 decibels200 decibels280 decibels