Quadrant (quad) - Unit Information & Conversion
🔄 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° | 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° | 2π | 400 | 1 |
Quadrant Conversion Formulas
To Degree:
To Radian:
To Gradian:
To Arcminute:
To Arcsecond:
To Turn:
To Revolution:
To Gon:
To Mil:
Frequently Asked Questions
Formula: Degrees = Quadrants × 90 Examples:
- 1 quadrant = 90°
- 2 quadrants = 180°
- 3 quadrants = 270°
- 4 quadrants = 360°
- 0.5 quadrants = 45° Quadrants to Degrees converter →
Convert Quadrant
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