use the slider to change the angle in steps of 5 degrees

How can we be sure that the lengths marked are what they claim to be?[br][i]Tangere[/i] is Latin for the present active infinitive of tangō. "to touch, to grasp" (1). Why is the tangent called that?[br][i]Secāre[/i] is the Latin present active infinitive of secō. (2) It means to cut or divide. Why is the secant called that?[br][br]1. [url]http://en.wiktionary.org/wiki/tangere[/url][br]2. [url]http://en.wiktionary.org/wiki/seco#Latin[/url]