A kangaroo word, a word that contains other words within it without rearranging letters (but being able to ignore letters). For example, encourage contains the words courage, age, cur, enrage, etc.
Yes. The valley fold is the exact opposite of a mountain fold. For the mountain fold, the middle goes up, and for the valley fold, the middle goes down.
Your exterior angle will be alternately and oppositely equal to the interior angle, since the lines between which the triangle lies in the proof diagram will be parallel. The sum...
