A quadrantal angle is one that is in the standard position and has a measure that is a multiple
of 90° (or π/2 radians). A quadrantal angle will have its terminal lying along an x or y axis.

In the figure above, drag the point A around and see which angles are quandrantal angles.

Other trigonometry topics

Angles

• Angle definition, properties of angles
• Standard position on an angle
• Initial side of an angle
• Terminal side of an angle
• Quadrantal angles
• Coterminal angles

Trigonometric functions

• Introduction to the six trig functions
• SOH CAH TOA memory aid


• Sine function (sin) in right triangles
• Graphing the sine function
• Sine waves


• Cosine function (cos) in right triangles
• Graphing the cosine function


• Tangent function (tan) in right triangles
• Graphing the tangent function


• Cotangent function cot (in right triangles)
• Secant function sec (in right triangles)
• Cosecant function csc (in right triangles)

Solving trigonometry problems

• The general approach
• Finding slant distance along a slope or ramp
• Finding the angle of a slope or ramp