| In Treatise on the quadrilateral al-Tusi gave the first extant exposition of the whole system of plane and spherical trigonometry. |
| I worked out the equivalent points on a rectilinear grid using trigonometry. |
| The mathematics curriculum grew accordingly to include algebra, trigonometry, and sometimes even Newton's fluxional calculus. |
| The mathematical part of the Aryabhatiya covers arithmetic, algebra, plane trigonometry and spherical trigonometry. |
| Hall apparently is ignorant of spherical trigonometry where the sum of the interior angles of every triangle exceeds 180 degrees. |
| We use these values to estimate the maximum downthrow of the Skinos fault as 1.12 km from basic trigonometry. |
