Answer
$72^0$ F
Work Step by Step
The question asks us for the temperature at 3:30 AM.
3:30 AM is located at the halfway point between 3 AM and 4 AM, more towards the right of the graph as AM is after midnight, and before noon.
Run your finger down this line to the first black line drawn in the top-half of the graph, representing the temperature recorded.
We can see that the reading at 3:30 AM is $72^0$F.
