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:
You really want to measure the circumference of something but there doesn't seem to be anything round around. That's when you remember, "Mah Walnuts! (まわ)." The walnuts in your pocket have an easy edge to measure.
I'm collecting coins with serrated edges.
If there's something you love or are passionate about, you should stick with it regardless what the other people say.
I'm worried about what other people are thinking about me.