[ot][ot][ot][personal] whirligig small thoughts

[Undescribed Horrific Abuse, One Victim & Survivor of Many]

ok ummmmmmmmmmmmmmmmmmmmm

so we have a wedge covering an angle of dtheta
the thickness of the wedge is roughly rdtheta

the wedge can be thought of as a stack of triangles where each triangle umm

- is r long
- is r dtheta wide [fixed mistake with editing]
- has an area of 1/2 base * height = 1/2 r * r dtheta = 1/2 r^2 dtheta
[fixed mistake with editing]