Took Frank for a walk this evening.

Aetat: 7. “Dear Papa, what is a right angle?”

I did not think Euclid’s definition would illuminate the childish mind, so I replied “You see that Chimney?”

“Yes, dear P.”

“Well it is strait up, isn’t it?”

“Yes.”

“And the top of the roof is straight along.”

“Yes.”

“Well then the angle or corner that one line makes with one another, just as the line of the side of that chimney makes with the line of the roof is called a right angle. An angle is a corner, and that particular shape of angle or corner is called a right angle.”

“I understand that dear P.”

The little man always says dearp, it is his abbreviation of short for dear papa.

“I think you do.”

“And what is a wrong angle, dearp.”