My brother has a cold and a fever of 38 degrees Celsius.
What temperature do you usually set the AC to?
I think about 24 degrees is just right for me.
The kanji degree can mean both degree in terms of angles and degree in terms of temperature. This word is how you talk about these things. Just attach it to a number and you have yourself the number of degrees that something is. After the numbers 1, 2 and 3 (and in some other situations) this can also mean times.
The reading is the same as the kanji reading you learned. When writing out the answer to this reading, omit the 〜 as it's only there to let you know that some other word should come before it.