What is the angle between the line of sight and the horizontal when an observer looks downward?

angle of depression

What is the angle between the line of sight and the horizontal when an observer looks upward?

angle of elevation

What is the term that describes the distance around a circle? 

circumference 

How many degree are in an entire triangle?

180 degrees 

How many degrees make up an entire circle?

360 degrees

What is the Pythagorean Theorem?

 a² + b² = c²

What triangle has at least two sides congruent?

isosceles triangle

What is the triangle with NO two sides congruent?

scalene triangle