Chapter 10 - NCPN

27. The figure at the right shows
a Ferris Wheel with a radius of
26 feet. Point A represents a
30° rotation of the wheel from
its starting position. Point B
represents an additional θ°
rotation of the Ferris Wheel.
a. The x-coordinate of point B
is 26 cos (θ + 30°). Use an
angle sum identity to write
this expression in terms of
cos θ and sin θ. 13 3 cos θ – 13 sin θ
b. The y-coordinate of point B
is 26 sin (θ + 30°). Use an
angle sum identity to write this
expression in terms of cos θ
and sin θ. 13 3 sin θ + 13 cos θ
c. What are the coordinates of
point B if θ = 60° (0, 26)
d. What are the coordinates of
point B if θ = 150° (–26, 0)
Mixed Review
Find the constant of variation, k, in each joint variation. Then
write the joint variation equation.
28. z = 30 when x = –3 and y = 5 k = –2, z = –2xy
29. z = 36 when x = 2 and y = 12 k = 1.5, z = 1.5xy
30. The city hall custodial staff arranged 26 chairs in the first row
of a meeting room for a town meeting. Each additional row
had 2 more chairs than the previous row. There were 12 rows
altogether. How many chairs are in the meeting room 444
478 Chapter 10 Trigonometric Functions and Identities