LESSON TENTH.
REVIEW.
Read all the right angles formed by the lines a b and c d. (Diagram [10].)
Why are the adjacent angles c e b, b e d, right angles?
What is a right angle?
Read four right angles whose vertices are at n.
Which is the greater, the right angle p q r, or the right angle t s u?
Can one right angle be greater than another?
Read six acute angles whose vertices are at n.
Why is m n g an acute angle?
What is an acute angle?
Which is greater, the acute angle m n g, or the acute angle l n m?
May one acute angle be greater than another?
What three acute angles are equal to one right angle?
Diagram 10.
Which of the two acute angles v f w, y x z is the greater?
Read four obtuse angles whose vertices are at n.
Why is f n m an obtuse angle?
What is an obtuse angle?
What does obtuse mean? Acute?
By what other name are both called?
Which is greater, the large acute angle 1 4 2, or the small obtuse angle 1 4 3?
How much greater than the right angle is the obtuse angle f n l?
How much less than a right angle is f n i?
Diagram 11.