Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you: The reading for this is the same as the other "to rise" word, 上がる. Nice how that works, right? So, just associate the two and you have yourself a reading.
When the teacher said that, many hands were raised.
I can’t believe that I’m nominated for the Mustache Award.
Tom's name was mentioned at the time, wasn't it?