Language of Trigonometry

Adam Z. Dotson


Classify the angle for the given measure of
an angle.

177° Obtuse Angle

90° < 177° < 180°

 

87.177° Acute Angle

0° < 87.177° < 90°

Radians to degrees.

π/2 radian =  π/2 × 180°/π = 180°/2 = 90°

Radias, r   Arc Length, s   Ɵ = Central Angle

r = 5 feet s = 30 feet

Ɵ = s/r   Ɵ = 30ft/5ft = 6 radians

 

r = 8 yards s = 18 yards

Ɵ = s/r   Ɵ = 18yd/8yd = 9/4 radians

 

Central angles are angles formed by any two
radii in a circle. The vertex is the center
of the circle. In Figure 1, ∠ AOB is a
central angle.

 

Figure 1 A central angle of a circle.

  

Source: http://www.cliffsnotes.com/math/geometry/circles/central-angles-and-arcs