More simply, the angle at the centre is double the angle at the circumference. Angle OGH (\(y\)) = angle OHG because triangle GOH is also isosceles. Lengths OH and OG are also both radii.

Practise finding angles in right-angled triangles with this quiz. You may need a pen and paper to help you with your answers. Architect's plans with trigonometry diagrams. Architecture is the ...

All it is is a device that measures the angle between two objects. The sextant makes use of two mirrors. With this sextant, one of the mirrors ( mirror A in the diagram) is half-silvered ...