Quadrant (quad) - Unit Information & Conversion

Symbol:quad
Plural:quadrants
Category:Angle

🔄 Quick Convert Quadrant

What is a Quadrant?

Quadrant is 1/4 of a full circle, equal to 90 degrees or π/2 radians. Used in coordinate systems, navigation, and geometry to describe quarter-circle sections. 4 quadrants = 360 degrees = full circle.

History of the Quadrant

Named from Latin "quadrans" (quarter). Used since ancient times in astronomy, navigation, and cartography. Essential for coordinate plane systems and compass directions (NE, SE, SW, NW quadrants).

Quick Answer

What is a Quadrant? A quadrant is one-quarter of a full circle, equal to 90 degrees or π/2 radians. Used to divide coordinate planes, compass directions, and circular measurements into four equal sections. 1 quadrant = 90° = π/2 rad = 100 gradians. Use our angle converter for instant conversions.

Key Facts: Quadrant

Property Value
Symbol quad
Quantity Angle
System Metric/SI Derived
Derived from Radian
Category Angle
Standard Body NIST / ISO

Definition

1 quadrant = 1/4 of a full circle = 90 degrees = π/2 radians ≈ 1.5708 radians

Key conversions:

  • 1 quadrant = 90 degrees
  • 1 quadrant = π/2 ≈ 1.5708 radians
  • 1 quadrant = 100 gradians (or gons)
  • 4 quadrants = 360 degrees (full circle)
  • 2 quadrants = 180 degrees (straight angle)

Symbol: quad or Q (sometimes written as "right angle")

Common Uses

Coordinate Systems: Cartesian plane divided into four quadrants (I, II, III, IV). Navigation: Compass quadrants (NE, SE, SW, NW) for direction description. Astronomy: Celestial sphere divided into quadrants for star mapping. Geometry: Right angles and perpendicular measurements in construction and design.

Real-World Examples

Coordinate System Quadrants: Detailed Breakdown

How the Cartesian plane divides into four sections:

Quadrant X Sign Y Sign Angle Range Examples
I (First) Positive Positive 0° to 90° (5, 3), (1, 1), (10, 7)
II (Second) Negative Positive 90° to 180° (-5, 3), (-1, 1), (-10, 7)
III (Third) Negative Negative 180° to 270° (-5, -3), (-1, -1), (-10, -7)
IV (Fourth) Positive Negative 270° to 360° (5, -3), (1, -1), (10, -7)
On Axes 0 or varies 0 or varies 0°, 90°, 180°, 270° (5, 0), (0, 3), (-4, 0)

Rule: Points ON the axes themselves belong to NO quadrant (axis points only)

Trigonometric Function Signs by Quadrant

How sine, cosine, and tangent change signs:

Quadrant Sine Cosine Tangent Remember
I (0°-90°) + + + All positive
II (90°-180°) + - - Sine positive
III (180°-270°) - - + Tangent positive
IV (270°-360°) - + - Cosine positive

Mnemonic: "All Students Take Calculus" = Quadrants 1-4 with + functions

Historical Quadrant Navigation Instrument

The astronomical quadrant used for celestial navigation:

Feature Description Measurement
Shape Quarter-circle (90° arc) 1 quadrant = 90°
Arm length Sighting arm (radius) Typically 60-120 cm
Scale Degree marks along arc 0° to 90° divisions
Plumb bob Hanging weight for vertical Gravity reference
Peep sights Holes for star alignment Two sighting points
Purpose Measure star altitude Above horizon angle
Navigation use Determine latitude Using North Star

Historical note: Used by explorers and navigators from 1300s-1700s; superseded by sextant

Compass Navigation: Cardinal Quadrants

Traditional navigation using quadrant directions:

Direction Compass Bearing Quadrant In Degrees In Radians
North N 0° or 360° 0 or 2π
Northeast NE I 45° π/4
East E I/II 90° π/2
Southeast SE II/III 135° 3π/4
South S III 180° π
Southwest SW III/IV 225° 5π/4
West W IV/I 270° 3π/2
Northwest NW IV/I 315° 7π/4

Application: Traditional navigation references bearings in terms of quadrants (e.g., "East-Southeast")

Architectural Applications

Where quadrants appear in building design:

Application Quadrant Use Example
Right angles 1 quadrant = 90° Square room corners
Arched doorways Quarter-circle arch Semicircle = 2 quadrants
Domes Hemispherical = 2 quadrants Half-sphere structure
Spiral stairs Each turn ≈ 1 quadrant Full turn = 4 quadrants
Circular gardens Divided into 4 sections Quadrant lawn areas
Rotundas 4-quadrant sections Octagonal/circular buildings

Unit Conversion Reference

Quick conversions between quadrants and other angle units:

Quadrants Degrees Radians Gradians Revolutions
0.5 45° π/4 50 1/8
1 90° π/2 100 1/4
1.5 135° 3π/4 150 3/8
2 180° π 200 1/2
3 270° 3π/2 300 3/4
4 360° 400 1

Quadrant Conversion Formulas

To Degree:

1 quad = 90 °
Example: 5 quadrants = 450 degrees

To Radian:

1 quad = 1.570796 rad
Example: 5 quadrants = 7.853982 radians

To Gradian:

1 quad = 100 grad
Example: 5 quadrants = 500 gradians

To Arcminute:

1 quad = 5400 ′
Example: 5 quadrants = 27000 arcminutes

To Arcsecond:

1 quad = 324000 ″
Example: 5 quadrants = 1620000 arcseconds

To Turn:

1 quad = 0.25 turn
Example: 5 quadrants = 1.25 turns

To Revolution:

1 quad = 0.25 rev
Example: 5 quadrants = 1.25 revolutions

To Gon:

1 quad = 100 gon
Example: 5 quadrants = 500 gons

To Mil:

1 quad = 1600 mil
Example: 5 quadrants = 8000 mils

Frequently Asked Questions

Formula: Degrees = Quadrants × 90 Examples:

Convert Quadrant

Need to convert Quadrant to other angle units? Use our conversion tool.