For a right-angled triangle, follow these steps to calculate an angle \(Ɵ\), when two sides are given: Note that scientific calculators need to be used for trigonometry and should be in degrees mode.

The gnomon is a right-angled triangle. The slanting side is at an angle of 28.4° to the ground, meant to match what was thought to be Delhi’s latitude in those days (it is taken as 28.7° today).