"Area and Arch Length of Circular Sector
'<hr /><div style="max-width:110mm;"><img style="height:60pt;" class="side" alt="sector-chord.png" src="https://calcpad.eu/media/math/area/sector-chord.png"></div>
'Dimensions
'Radius -'r = ?
'Chord -'a = ?
'<!--
#if a ≤ 2*r
	'<-->
	'Angle
	α = 2*asin(a/(2*r))'&deg;
	'Area
	A = π*r^2*α/360
	'Arch length
	S = π*r*α/180
	'<!--
#else
	'<-->
	'Chord <i>a</i> must be less or equal to 2&middot;<i>r</i>
	'<!--
#end if
'<-->1	1