Exploring the Basics of the Unit Circle

What does the variable 'r' represent in the standard equation of a circle?

• Area of the circle

• Diameter of the circle

• Radius of the circle

• Circumference of the circle

If the radius of the circle is 5, what is the simplified equation of the circle centered at the origin?

• x^2 + y^2 = 5

• x^2 + y^2 = 10

• x^2 + y^2 = 30

• x^2 + y^2 = 25

If the equation is x^2 + y^2 = 25, which ordered pair would satisfy this equation?

• (6, 0)

• (3, 4)

• (5, 5)

• (0, 5)

What does the ordered pair (0, -5) represent in the context of the circle equation x^2 + y^2 = 25?

• A point inside the circle

• A point outside the circle

• The center of the circle

• A point on the circle at the bottom

What is the sine of theta if the ordered pair is (3/5, 4/5)?

• 5/3

• 5/4

• 4/5

• 3/5

What is the cosine of theta for the ordered pair (3/5, 4/5)?

• 3/5

• 4/5

• 5/3

• 5/4

What is the tangent of theta for the ordered pair (3/5, 4/5)?

• 3/4

• 5/3

• 3/5

• 4/3

What is the result of cosine of negative 3 pi over 2?

• 0

• Undefined

• 1

• -1

What is the secant of seven pi over two?

• Undefined

• 0

• -1

• 1

What is the tangent of negative three pi?

• Undefined

• 1

• 0

• -1