Persia · c. 1267-c. 1320
Kamal al-Din al-Farisi
Kamal al-Din al-Farisi was mathematician and optical scientist. He explained the primary and secondary rainbow through refraction and internal reflection in transparent spheres.
Biographical and historical reference works document Kamal al-Din al-Farisi’s role and the mathematical work summarized on this page.
3-5, 6-8, 9-12, College
The person and the work
Biography
Kamal al-Din al-Farisi was mathematician and optical scientist associated with Persia. He explained the primary and secondary rainbow through refraction and internal reflection in transparent spheres.
His optical analysis combined geometry, controlled glass-sphere experiments, and angle tracking. Together, these contributions connect geometry and measurement, trigonometry, and statistics and probability to the working problems, tools, and questions of the period.
Mathematical contribution
What this hero added or preserved
Core mathematical work
He explained the primary and secondary rainbow through refraction and internal reflection in transparent spheres.
Method, teaching, or application
His optical analysis combined geometry, controlled glass-sphere experiments, and angle tracking.
Why this matters
The larger lesson
Kamal al-Din al-Farisi shows that mathematics grows through proof, calculation, observation, design, teaching, or careful records. The lasting lesson is that geometry and measurement, trigonometry, and statistics and probability can turn a difficult question into a method another person can inspect and reuse.
Place the work in time
Timeline
- c. 1267
Life and working period
Kamal al-Din al-Farisi worked as mathematician and optical scientist in Persia.
- Legacy
Lasting mathematical connection
His optical analysis combined geometry, controlled glass-sphere experiments, and angle tracking.
Key idea
Geometry turns dimensions into consequences
Kamal al-Din al-Farisi’s work demonstrates that lengths and angles can determine area, shape, position, or motion.
A rectangle 15 units by 9 units has area 135 square units and perimeter 48 units.
Try it yourself
Measure a rectangle
A rectangle is 15 units long and 9 units wide. Find its area and perimeter.
- Multiply length by width for area.
- Add length and width, then double for perimeter.
- Attach the correct units.
Show the answer
The area is 135 square units, and the perimeter is 48 units.
Math at work
Engineers and architects use the same habits
Engineers and architects use geometry and measurement to plan, compare, test, or communicate decisions. Kamal al-Din al-Farisi’s work provides a historical example of that connection.
Keep curiosity alive
A little-known fact
His optical analysis combined geometry, controlled glass-sphere experiments, and angle tracking.
Kamal al-Din al-Farisi matters because of only one famous formula or anecdote.
The documented record is broader: He explained the primary and secondary rainbow through refraction and internal reflection in transparent spheres.
Keep exploring
Connected learning paths
Practice these ideas
- GeometryExplore shapes, angles, area, perimeter, volume, and classification.
- Advanced GeometryPractice coordinate geometry, transformations, vectors, and solids.
- TrigonometryUse angles, right triangles, radians, and trigonometric functions.
- Statistics & ProbabilityWork with averages, data sets, probability, and spread.