"Area and Circumference of Circle
'<hr /><div style="max-width:100mm;"><img style="height:70pt;" class="side" alt="circle.png" src="https://calcpad.eu/media/math/area/circle.png"></div>
'Diameter
'2&middot;<i>r</i> ='d = ?
'Area
A = π*d^2/4
'Circumference
P = π*d
'1