If you know the reading of the word 長い from level 6 you'll know the reading for this word too. Only difference is the さ at the end, which is hiragana so it should be easy to read.
Weird, I was sure I measured the length properly.
This snake is sold in three centimeter long pieces.
The length of the bridge was one of the main reasons why I faltered. It was just too long for me.